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The presenting symptoms may vary by the site of the tumor. The tumors can spread by direct invasion into the surrounding tissues and also by metastasis to regional lymph nodes and internal organs such as the liver and lungs. These tumors usually present with bleeding, change in bowel habits, or lower abdomen discomfort.


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SYNONYMS Colon cancer
INCIDENCE 134,000 new cases and 55,000 deaths
10% of cancer related deaths in the United States
<20% occur below 50 years
Highest in USA and Eastern Europe

Reduced fiber content decreases the transit time of stool, leading to altered bacterial flora. The bacteria may break down carbohydrates into toxic and potentially carcinogenic by-products. Refined foods often lack vitamins A, C, and E (which act as oxygen free radical scavengers) which may allow for further cellular damage.

  Excess energy intake relative to requirements
  Low content of unabsorbable vegetable fiber
  High content of refined carbohydrates
  Intake of red meat
  Decreased intake of protective micronutrients
Meat consumption and risk of colorectal cancer.

Chao A, Thun MJ, Connell CJ, McCullough ML, Jacobs EJ, Flanders WD, Rodriguez C, Sinha R, Calle EE.

Epidemiology and Surveillance Research, American Cancer Society, Atlanta, Ga 30329-4251, USA.
JAMA. 2005 Jan 12;293(2):172-82. Abstract quote  

CONTEXT: Consumption of red and processed meat has been associated with colorectal cancer in many but not all epidemiological studies; few studies have examined risk in relation to long-term meat intake or the association of meat with rectal cancer.

OBJECTIVE: To examine the relationship between recent and long-term meat consumption and the risk of incident colon and rectal cancer.

DESIGN, SETTING, AND PARTICIPANTS: A cohort of 148 610 adults aged 50 to 74 years (median, 63 years), residing in 21 states with population-based cancer registries, who provided information on meat consumption in 1982 and again in 1992/1993 when enrolled in the Cancer Prevention Study II (CPS II) Nutrition Cohort. Follow-up from time of enrollment in 1992/1993 through August 31, 2001, identified 1667 incident colorectal cancers. Participants contributed person-years at risk until death or a diagnosis of colon or rectal cancer.

MAIN OUTCOME MEASURE: Incidence rate ratio (RR) of colon and rectal cancer.

RESULTS: High intake of red and processed meat reported in 1992/1993 was associated with higher risk of colon cancer after adjusting for age and energy intake but not after further adjustment for body mass index, cigarette smoking, and other covariates. When long-term consumption was considered, persons in the highest tertile of consumption in both 1982 and 1992/1993 had higher risk of distal colon cancer associated with processed meat (RR, 1.50; 95% confidence interval [CI], 1.04-2.17), and ratio of red meat to poultry and fish (RR, 1.53; 95% CI, 1.08-2.18) relative to those persons in the lowest tertile at both time points. Long-term consumption of poultry and fish was inversely associated with risk of both proximal and distal colon cancer. High consumption of red meat reported in 1992/1993 was associated with higher risk of rectal cancer (RR, 1.71; 95% CI, 1.15-2.52; P = .007 for trend), as was high consumption reported in both 1982 and 1992/1993 (RR, 1.43; 95% CI, 1.00-2.05).

CONCLUSIONS: Our results demonstrate the potential value of examining long-term meat consumption in assessing cancer risk and strengthen the evidence that prolonged high consumption of red and processed meat may increase the risk of cancer in the distal portion of the large intestine.


Familial polyposis syndromes  
Hereditary nonpolyposis colorectal cancer (HNPCC)  

Hyperplastic Polyposis Association With Colorectal Cancer

Barbara A. Leggett, M.D., F.R.A.C.P.; Benedict Devereaux, M.B.B.S., F.R.A.C.P.; Kelli Biden, B.Sc.; Jeffrey Searle, M.D., F.R.C.P.A.; Joanne Young, Ph.D.; Jeremy Jass, D.Sc., F.R.C.Path.

From the Conjoint Gastroenterology Research Laboratory, Royal Brisbane Hospital Research Foundation Clinical Research Center, Brisbane, Australia (B.A.L., K.B., J.Y.); the Department of Gastroenterology, Royal Brisbane Hospital (B.D.), Department of Pathology, Royal Brisbane Hospital; and the Department of Pathology, University of Queensland, Brisbane, Australia (J.J.).

Am J Surg Pathol 2001;25:177-184 Abstract quote

Hyperplastic polyposis is a loosely defined syndrome initially thought not to confer a clinically important predisposition to colorectal cancer.

The aim of the current study was to examine the clinical, histologic, and molecular features of a prospective series of cases meeting a strict definition of the condition.

Twelve patients were identified, seven of whom had developed colorectal cancer. Most polyps were hyperplastic, but 11 patients also had polyps containing dysplasia as either serrated adenomas, mixed polyps, or traditional adenomas.

The mean percentage of dysplastic polyps in patients with cancer was 35%, and in patients without cancer, 11% (p < 0.05). Microsatellite instability (MSI) was present in 3 of 47 hyperplastic polyps and two of eight serrated adenomas. Kras was mutated in 8 of 47 hyperplastic polyps and two of eight serrated adenomas. No polyps showed loss of heterozygosity of chromosomes 5q, 1p, or 18q. Two of seven cancers showed a high level of MSI.

It is concluded that hyperplastic polyposis is associated with a high risk of colorectal cancer. Hyperplastic polyps are the dominant type of polyp, but most cases have some dysplastic epithelium. A higher proportion of dysplastic polyps is associated with increased cancer risk. Clonal genetic changes are observed in some hyperplastic polyps and serrated adenomas.

Sporadic colorectal cancers with microsatellite instability and their possible origin in hyperplastic polyps and serrated adenomas.

Hawkins NJ, Ward RL.

School of Pathology, University of New South Wales, Sydney, Australia.

J Natl Cancer Inst 2001 Sep 5;93(17):1307-13 Abstract quote

BACKGROUND: Microsatellite instability (MSI) is seen in 10%-15% of sporadic colorectal cancers mostly in the right colon, but the precursors of cancers with MSI remain unknown. We examined whether sporadic cancers with MSI arise from pre-existing benign proliferative lesions (such as hyperplastic polyps or serrated adenomas [together denoted as "serrated polyps"]).

METHODS: The frequency of benign epithelial lesions (serrated polyps and conventional adenomas) was determined by histologic review of resection specimens from individuals (n = 29) with sporadic colorectal cancer with MSI and from a matched control group (n = 29) with cancer showing microsatellite stability (MSS). MSI status, expression of mismatch repair enzyme (product of the human mut-L homologue 1 [hMLH1] gene), and hMLH1 gene promoter methylation in the benign lesions were determined. Data were analyzed by the chi-square test, by Wilcoxon's rank-sum test, and by conditional logistic regression as appropriate, and a two-sided probability less than.05 was considered to be statistically significant.

RESULTS: Individuals with cancers showing MSI were more likely to harbor at least one serrated polyp than individuals with cancers showing MSS (odds ratio = 4.0; 95% confidence interval = 1.1 to 14.2; P =.03), but the frequency of conventional adenomas was the same in both groups (P =.52, Mann-Whitney test). Loss of hMLH1 protein expression was seen in lesions from 10 of 13 patients with MSI, but no loss was seen in lesions from four patients with MSS (P =.02, Fisher's exact test). Loss of hMLH1 protein expression was associated with MSI in assessable lesions. The hMLH1 promoter was methylated in all assessable serrated polyps from patients with cancers showing MSI but in none of the lesions from patients with MSS cancers.

CONCLUSIONS: Some right-sided hyperplastic polyps may give rise to sporadic colorectal carcinomas with MSI. Methylation of the hMLH1 gene promoter within neoplastic cell subpopulations may be a critical step in the progression to carcinoma. The frequency with which benign lesions progress to cancer with MSI is unknown.

Ulcerative colitis  



In general, three major and overlapping pathways of tumor progression have been described:

Chromosomal instablilty pathway
Microsatellite instability pathway (MSI)
CpG island methylator phenotype pathway (CIMP)

Differential Expression of the AP-1 Transcription Factor Family Members in Human Colorectal Epithelial and Neuroendocrine Neoplasms

Wanghai Zhang, MD, PhD, etal.
Am J Clin Pathol 2005;124:11-19 Abstract quote

We immunohistochemically examined 75 human colorectal neoplasms (adenoma, 27; adenocarcinoma, 24; neuroendocrine carcinoma, 24) for the expression of activator protein (AP)-1 family proteins. Nuclear and cytoplasmic expression levels of c-Jun and Fra-1 proteins were markedly elevated in adenomas, adenocarcinomas, and neuroendocrine carcinomas compared with nonneoplastic colorectal epithelial cells. JunB also was overexpressed in these tumors but with a predominantly cytoplasmic staining pattern.

Overexpression of Fra-2 was evident in carcinomas but less frequent in adenomas. Expression levels of JunD and c-Fos were high in nonneoplastic colorectal epithelial cells and remained so in neoplasms. FosB was undetectable in nonneoplastic and neoplastic colorectal tissues. Neuroendocrine carcinomas exhibited an AP-1 expression profile similar to adenocarcinomas except for infrequent overexpression of c-Jun in poorly differentiated variants. Hierarchical clustering separated the majority of malignant from benign tumors based on AP-1 expression patterns. AP-1 transcription factor family members are expressed differentially in nonneoplastic and neoplastic colorectal tissues.

Up-regulation of c-Jun and Fra-1 is an early event in human colorectal tumorigenesis. Overexpression of Fra-2 may participate in tumor progression.
Support for hMLH1 and MGMT silencing as a mechanism of tumorigenesis in the hyperplastic-adenoma-carcinoma (serrated) carcinogenic pathway in the colon.

Oh K, Redston M, Odze RD.
Hum Pathol. 2005 Jan;36(1):101-11. Abstract quote

Summary Background Down-regulation of DNA repair genes has been proposed as an important mechanism of tumorigenesis in some colon cancers. This mechanism has also recently been implicated in the newly postulated hyperplastic polyp-serrated adenoma-carcinoma ("serrated") pathway of carcinogenesis, although this has never been investigated thoroughly. The aim of this study was to evaluate hMLH1, hMSH2, MGMT, as well as MIB-1, p53, and beta -catenin immunoexpression in an uncommon cohort of mixed colonic polyps that contain a combination of hyperplastic and adenomatous features (n = 21), and in some (n = 7), carcinoma as well.

Design The clinical, pathological, and immunophenotypic (hMLH1, hMSH2, MGMT, MIB-1, p53, and beta -catenin) properties of 28 mixed hyperplastic and adenomatous polyps of the colon (7 of which also contained carcinoma within the same lesion) were evaluated for the above immunopeptides in each of the different morphologic areas of the polyps, and the results were compared to traditional hyperplastic polyps, serrated adenomas, and conventional (nonserrated) adenomas.

Results Clinically, most mixed polyps with carcinoma occurred in the ascending colon (86%), and pathologically, the adenomatous component of most mixed polyps was serrated (96%). Mixed polyps, particularly those with carcinoma, showed loss of hMLH1 (33%), MGMT (37%), and even hMSH2 (11%) with significantly higher frequency compared to hyperplastic polyps, conventional adenomas, and serrated adenomas. More specifically, loss of hMLH1 and MGMT were more frequent in epithelium of higher neoplastic grade in mixed polyps. However, hMSH2 loss was only present in the adenoma component and never in the hyperplastic or carcinomatous areas of these polyps. Defects in MIB-1 proliferation indices and p53 were not significantly different among the same epithelial components in each of the polyp groups. However, conventional adenomas showed significantly higher rates of nuclear beta -catenin staining (100%) in comparison to the adenomatous component of mixed polyps (60%).

Conclusions Loss of hMLH1 and MGMT play a prominent role in the serrated pathway of carcinogenesis in the colon.
Inherited or acquired mutations of cancer suppressor genes in normal colon APC
Mismatch of repair genes
Methylation abnormalities leads to mucosa at risk APC
Protooncogene mutation leads to adenoma K-ras
Homozygous loss of additional cancer suppressor genes (p53 and LOH at 18q21
Additional mutations and gross chromosomal alterations leads to carcinoma Many genes
Progressive acquisition of genetic mutations

Populations with high prevalence of adenomas have high prevalence of cancer
Distribution of adenomas similar to carcinoma
Peak incidence of adenomas occurs before carcinoma
Early stage invasive carcinomas often associated with adenomatous tissue
Risk of cancer directly related to number of adenomas
Aggressive screening and removal of adenomas decreases the incidence of cancer

5q loss
Normal epithelium changes to adenoma
18q loss
Early adenoma changes to large adenoma
Takes place over many decades
17p loss
Late adenoma changes to early cancer
Takes place over 2-5 years
8p loss
Early cancer changes to late cancer
APC gene (5q21)

APC is regarded as a Gatekeeper gene

APC protein binds to microtubule bundles and promotes cell migration and adhesion
APC protein binds to cytoskeletal protein beta-catenin which is bound to E-cadherin

Beta-catenin binds to T cell factor-lymphoid enhancer factor (Tcf-Lef) proteins-this binding leads to stimulation of cell proliferation and inhibition of apoptosis

When APC binds to beta-catenin, it starts degradation of it, leading to inhibition of beta-catenin:Tcf signalling pathway

Mutations in the APC gene reduce the affinity of APC protein for beta-catenin

Net result is loss of intercellular contact and increased cytoplasmic pool of beta-catenin


Involvement of Arp2/3 complex in the process of colorectal carcinogenesis.

Otsubo T, Iwaya K, Mukai Y, Mizokami Y, Serizawa H, Matsuoka T, Mukai K.

Department of Pathology, Tokyo Medical University, Shinjuku-ku, Tokyo, Japan.
Mod Pathol. 2004 Apr;17(4):461-7. Abstract quote

Increased motility is one of the characteristics of cancer cells, and actin polymerization and disassembly are essential for cellular motility. Since actin-related protein (Arp) 2/3 complex acts as a nucleus for actin polymerization, in this study, we immunohistochemically investigated the expression of Arp2 and Arp3 in 175 colorectal tumors in various stages of neoplastic progression. Arp2 and Arp3 showed identical expression patterns, and both were expressed in the stromal cells around neoplastic tubules or glands and in the tumor cells themselves. The frequency of expression of Arp2 and Arp3 (Arp2 and 3) by the stromal cells increased with the atypia of the colorectal neoplasms, from 5.5% (3/55) in adenoma with mild or moderate atypia, to 11.8% (2/17) in adenoma with severe atypia, 53.3% (16/30) in intramucosal carcinoma, and 91.8% (67/73) in invasive carcinoma (P<0.0001). The frequency of expression of Arp2 and 3 in the tumor cells was similar and was 1.8% (1/55) in adenoma with mild or moderate atypia, 23.5% (4/17) in adenoma with severe atypia, 23.5% (7/30) in intramucosal carcinoma, and 32.9% (24/73) in invasive carcinoma.

Expression of Arp2 and 3 by the stromal cells was significantly correlated with nuclear accumulation of p53 in the tumor cells and stromal expression of CD10.

These results suggest that formation of Arp2/3 complex by both neoplastic and stromal cells contributes to the increased motility of both cell types and thus provides suitable conditions for invasion.
HNPCC genes

HNPCC is considered the caretaker genes

These are human mismatch repair genes and consist of 4 genes


Involved in genetic proofreading during DNA replication

Mutations in these genes lead to alterations in repeat sequences leading to microsatellite instability

An inherited mutant gene would still have normal repair activity because of remaining normal allele, however, these cells are susceptible to a second mutation

Phenotype of Microsatellite-Stable Colorectal Carcinomas With CpG Island Methylation.

Chirieac LR, Shen L, Catalano PJ, Issa JP, Hamilton SR.

From the *Department of Pathology, Division of Pathology and Laboratory Medicine, and daggerDepartment of Leukemia, Division of Cancer Medicine, University of Texas M. D. Anderson Cancer Center, Houston, TX; double daggerDepartment of Biostatistical Science, Dana-Farber Cancer Institute, Boston, MA; and section signEastern Cooperative Oncology Group,
Boston, MA.
Am J Surg Pathol. 2005 Apr;29(4):429-436. Abstract quote  

A distinctive pathway of colorectal carcinogenesis termed CpG island methylator phenotype is characterized by extensive DNA methylation in colorectal carcinoma (CRC) cells but not in nonneoplastic mucosa. Many CRCs with CpG island methylator phenotype have methylation of the hMLH1 mismatch repair gene and consequently have high levels of microsatellite instability (MSI-H). MSI-H confers distinctive clinical-pathologic features, but the phenotype of microsatellite-stable CRC with methylation has not been characterized in detail.

We therefore examined the clinical-pathologic features of 87 sporadic microsatellite-stable CRCs that had been characterized for methylation of p16, p14, MGMT, hMLH1, MINT1, MINT2, and MINT31. Regression analyses of each clinical-pathologic characteristic were run against the individual and aggregated methylation markers to evaluate and quantify associations. CpG island methylation was associated with right-sided carcinoma (odds ratio = 6.9, P = 0.03). Paucity of gland formation, indicating poor differentiation, was strongly associated with methylation (beta = -42.6, P = 0.0008), as were presence of cribriform glands (beta = 34.3, P = 0.02) and lack of corkscrew/serrated glandular pattern (beta = -32.5, P = 0.03).

Our epigenotype-phenotype correlation study shows that microsatellite-stable CRC with CpG island methylation have a distinctive pathologic phenotype with both similarities to and differences from MSI-H tumors.
K-ras (12p12) Most frequent activated oncogene, mutated in 50% of adenomas >1 cm
DCC (18q21)
(Deleted in Colon CA)
Expression is reduced or absent in 70-75% of cancers
p53 (17p) Variable losses in adenomas
Deletions of chromosome 4 occur early during the pathogenesis of colorectal carcinoma

Hum Pathol 2001:32:169-177

Performed loss of heterozygosity (LOH) studies using 19 polymorphic microsatellite markers
After precise microdissection of archival surgical cases, we determined LOH in DNA obtained from 23 colorectal adenocarcinomas, 20 colorectal adenomas, and from corresponding histologically normal-appearing colonic epithelial samples adjacent to the tumors and at the resection margins

We observed localized deletions of chromosome 4 at multiple regions in both carcinomas and adenomas
Identified deletions at 4 previously identified regions: R1 at 4q33-34 (18%-33%), R2 at 4q25-26 (45%-65%), R3 at 4p15.1-15.3 (35%-47%), and R4 at 4p16.3 (40%-49%).

Six of fifteen (40%) cases examined with deletions of chromosome 4 in either adenocarcinomas or adenomas had loss of the same parental alleles in adjacent histologically normal epithelium but not in epithelial samples from the surgical resection margins

The deletions, which commenced on the short arm of chromosome 4 (regions R3 and/or R4), were more extensive in adenocarcinomas, intermediate in length in adenomas, and least extensive in histologically normal epithelium

Suggest that there may be multiple putative tumor suppressor genes located on both arms of chromosome 4 whose inactivation are important early events in the pathogenesis of colorectal carcinoma

Expression of the ets-1 Proto-Oncogene in Human Colorectal Carcinoma

Toshiyuki Nakayama, etal.

Mod Pathol 2001;14:415-422 Abstract quote

The proto-oncogene, ets-1, is a transcription factor known to control the expression of a number of genes involved in extracellular matrix remodeling and has been postulated to play a role in cell migration and tumor invasion.

To elucidate the involvement of ets-1 in human colorectal carcinomas, we examined 41 cases of colorectal adenoma and 122 cases of colorectal carcinoma by immunohistochemistry and compared the degree of Ets-1 expression with the depth of carcinoma invasion.

In adenomas, 12 of 41 cases (29.3%) showed immuno-positivity for Ets-1. 12 of 27 cases (44.4%) of adenoma with high grade dysplasia showed immunopositivity for Ets-1. However, there was no positive case in low or moderate dysplasia of adenoma. In contrast, 103 of 122 cases (84.4%) of colorectal adenocarcinoma showed immunoreactivity for Ets-1 in the carcinoma cells themselves.

We investigated the relationship between pathological features in colorectal carcinoma and Ets-1 immunoreactivity of the tumor cells. Among the 122 cases of invasive carcinomas, Ets-1 immunoreactivity was significantly correlated with the depth grading of tumor invasion (P < .0001), the presence of lymph node metastasis (P < .05), lymphatic invasion (P < .01) and venous invasion (P < .05). However, Ets-1 expression did not correlate with histological differentiation. In situ hybridization also confirmed the presence of ets-1 mRNA in colorectal carcinomas. Expression of ets-1 mRNA was also detected in two of three human colorectal carcinoma tissues and in four of six different kinds of carcinoma cell lines by the reverse transcription polymerase chain reaction method.

These findings suggest that the expression of Ets-1 is one of the important factors related to carcinogenesis and/or tumor invasion of colorectal carcinoma.


Proliferating cell nuclear antigen as a marker of cell kinetics in aberrant crypt foci, hyperplastic polyps, adenomas, and adenocarcinomas of the human colon.

Shpitz B, Bomstein Y, Mekori Y, Cohen R, Kaufman Z, Grankin M, Bernheim J.

Department of Surgery B, Meir General Hospital, Kfar Saba, Israel

Am J Surg 1997 Oct;174(4):425-30 Abstract quote

BACKGROUND: One of the first steps in multistage colonic carcinogenesis is increased cell proliferation and an upward shift of the proliferation zone of colonic crypts. In the present study, progression in cell kinetics was followed up at all sequential stages of colonic carcinogenesis, starting with aberrant crypt foci (ACF), the earliest putative preneoplastic lesions, hyperplastic and dysplastic polyps, and invasive carcinomas.

MATERIALS AND METHODS: Colonic tissue and tumor specimens were prospectively obtained from 65 patients treated at our hospital for adenocarcinoma or malignant polyps. For identification of ACFs, dissected mucosal strips obtained from patients with colorectal cancer were stained with 0.1% methylene blue and scanned under dissecting microscope. Paraffin-embedded ACFs and macroscopic lesions were serially sectioned, deparaffinized, and stained with a monoclonal antiproliferating cell nuclear antigen (PCNA) antibody. The PCNA-labelling index (PCNA-LI), expressed as a ratio of positively stained nuclei to total nuclei counted, was calculated separately for basal, middle, and upper colonic crypt compartments. A comparison of the PCNA-LI was made for each compartment in normal mucosa, and hyperplastic and dysplastic lesions.

RESULTS: A stepwise increase in the PCNA-LI was observed during neoplastic progression of colonic lesions. The two most important variables of increased cell proliferation, expressed as PCNA-LI per crypt compartment, were the presence of dysplasia and the size of dysplastic lesions. CONCLUSIONS: In colorectal carcinogenesis, hyperproliferation with upward expansion of proliferative compartment is a characteristic feature at all stages of malignant progression.

Phenotypic and genotypic characteristics of aberrant crypt foci in human colorectal mucosa.

Nucci MR, Robinson CR, Longo P, Campbell P, Hamilton SR.

Department of Pathology and Oncology Center, The Johns Hopkins University School of Medicine and Hospital, Baltimore, MD 21205-2196, USA.

Hum Pathol 1997 Dec;28(12):1396-407 Abstract quote

Aberrant crypt foci (ACF) in colorectal mucosa are proposed to be the earliest morphological lesion in the development of neoplasia, but their characteristics remain controversial.

We therefore studied the epithelial phenotype and genotype of ACF from patients with familial adenomatous polyposis (FAP) and of sporadic ACF by evaluating glycoprotein markers associated with neoplasia (lectins Dolichus biflorus agglutinin and peanut agglutinin; monoclonal antibody CA 19-9 against sialyl Lewis-a blood group substance), expression of proliferating cell nuclear antigen, and ras proto-oncogene mutations. The utility of the markers was established by comparing adenomas and hyperplastic polyps. Most FAP ACF resembled adenomas and were found to differ from sporadic ACF in their high frequency of dysplasia, staining with Dolichus biflorus agglutinin, expression of sialyl Lewis-a, proliferation in the epithelium of upper crypts, and low frequency of ras gene mutations (P = .04 to < .0000001). By contrast, sporadic ACF and a subset of FAP ACF had phenotypic characteristics resembling hyperplastic polyps but usually had ras mutations, which were inversely related to dysplasia (P = .00009).

Our findings suggest that "aberrant crypt focus" is a generic term analogous to "polyp" and requires further histopathologic, phenotypic, or genotypic classification into dysplastic and heteroplastic (hetero = other, plasia = form) types. Dysplastic ACF represent potential precursors to colorectal adenomas and adenocarcinomas, but heteroplastic ACF appear to be associated, rather than precursor, lesions.

Role of bax Mutations in Apoptosis in Colorectal Cancers With Microsatellite Instability

Catherine Miquel, MD, etal.
Am J Clin Pathol 2005;123:562-570 Abstract quote

Half of colorectal tumors with microsatellite instability contain frameshift mutations in the (G)8 tract of bax, a major apoptosis effector, but their functional significance remains unclear.

We studied the role of bax mutations on bax expression and apoptosis in 59 primary colorectal cancers of which 41 were microsatellite unstable. Tumors were screened for bax(G)8 mutations and evaluated immunohistochemically for bax, bcl-2, and p53 protein expression and apoptotic (M30 cytoDEATH) and proliferative (Ki-67) indexes.

We identified bax(G)8 mutations in 20 (49%) of 41 unstable tumors; the mutations were associated significantly with proximal, poorly differentiated, or mucinous adenocarcinomas. Most bax-mutated cases displayed a bax-immunonegative zone in all or part of the tumor that was proved to correspond to biallelic bax(G)8 mutations by microdissection and to confer growth advantage to the tumor by decreasing apoptosis compared with adjacent bax-immunopositive tumor. Biallelic bax(G)8 mutations are subject to positive selection pressure and might disable apoptosis in colorectal cancer.

Increased apoptosis in infiltrating mononuclear cells of colorectal cancer.

Chen GG, Lee JF, Chan UP, Xu H, Ip PC, Lau WY.

Department of Surgery (Drs Chen, Lee, Xu, and Lau and Ms Chan and Ms Ip) and Sir Y. K. Pao Center for Cancer (Dr Chen), Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong.

Arch Pathol Lab Med 2002 Jun;126(6):686-91 Abstract quote

Context.-Disturbance in apoptosis has been proposed as one of the mechanisms involved in the immune response targeting tumor outgrowth. How colorectal cancer cells escape from attack by the immune system is not yet fully understood.

Objective.-To investigate apoptotic molecules associated with colorectal cancer counterattack. Design and Setting.-Tissue samples of colon from 12 patients with colorectal cancer were collected and analyzed by immunostaining. In addition to tumorous tissues, corresponding nontumorous specimens of colon were obtained as controls.

Main Outcome Measures.-We examined the expression of Bcl-2, Bcl-xl, Bax, caspase-3, and inducible nitric oxide synthase in infiltrating mononuclear cells of colorectal cancer tissues and also in colorectal cancer tissues. The TUNEL assay was used to detect in situ apoptosis.

Results.-Apoptosis was barely detectable in specimens of colorectal cancer, which was consistent with an increase in Bcl-2 level and a decrease in caspase-3 level. In contrast, infiltrating mononuclear cells of tumorous tissues showed a marked increase in apoptosis compared with those of nontumorous tissues. The increased apoptosis might have resulted from an imbalance of antiapoptotic and proapoptotic molecules, as reflected by reduction of Bcl-2 level and elevation of Bax level. The elevated caspase-3 levels found in this study could be a downstream effector of the Bcl-2 and Bax apoptotic pathways. A significant increase in inducible nitric oxide synthase observed in the infiltrating mononuclear cells might contribute to immunosuppression seen in colorectal cancer.

Conclusion.-It is tempting to speculate that aberrant expression of apoptotic molecules and inducible nitric oxide synthase in infiltrating mononuclear cells provides the underlying mechanism through which colorectal cancer cells escape attack by the immune system and subsequently grow without control.

High Apoptotic Activity and Low Epithelial Cell Proliferation With Underexpression of p21WAF1/CIP1 and p27Kip1 of Mucinous Carcinomas of the Colorectum
Comparison With Well-Differentiated Type

Fumiyuki Akino, MD,1 Hiroyuki Mitomi, MD,1 Takatoshi Nakamura, MD,2 Yoshimasa Ohtani, MD,2 Masaaki Ichinoe, MD,1 and Isao Okayasu, MD

Am J Clin Pathol 2002;117:908-915 Abstract quote

We comparatively assessed 41 mucinous colorectal carcinomas (MUCs) and 620 non-MUC (well-, moderately, and poorly differentiated adenocarcinoma) cases for clinicopathologic findings; and 41 MUCs and 115 randomly selected non-MUCs also were studied for the following: (1) apoptotic activity and Ki-67 immunoreactivity; (2) immunohistochemical expression of p21WAF1/CIP1, p27Kip1, p53, and bcl-2; and (3) c-Ki-ras mutations.

The rates for lymph node involvement and peritoneal dissemination were higher in MUCs than in non-MUCs. Multivariate analysis showed MUCs to have a worse prognosis than well-differentiated adenocarcinomas. The Ki-67 labeling for MUCs was significantly lower than that for non-MUCs, whereas the apoptotic index was significantly higher than for the well-differentiated type. The labeling for p21WAF1/CIP1 and p27Kip1 was lower in MUCs (2.7% and 35.3%, respectively) than in well-differentiated adenocarcinomas (4.2% and 48.6%, respectively).

MUCs can be considered a different tumor from the well-differentiated type, with a poor prognosis owing to frequent lymph node metastasis and peritoneal dissemination, and characterized by high apoptotic and low proliferative activities associated with low p21WAF1/CIP1 and p27Kip1 expression.


Expression of CD10 by stromal cells during colorectal tumor development.

Ogawa H, Iwaya K, Izumi M, Kuroda M, Serizawa H, Koyanagi Y, Mukai K.

Department of Pathology, Tokyo Medical University, Tokyo, Japan, and the Division of Surgical Pathology and the Third Department of Surgery, Tokyo Medical University Hospital, Tokyo, Japan.

Hum Pathol 2002 Aug;33(8):806-11 Abstract quote

CD10 is a cell surface metalloprotease expressed by a variety of normal cell types, including lymphoid precursor cells, germinal center B lymphocytes, and some epithelial cells.

We noticed that stromal cells of some cancers are positive for CD10. In this study, we investigated the role of CD10 produced by the stromal cells of colorectal neoplasms in the progression of colorectal neoplasms. Immunohistochemical examination of CD10 and p53 was performed in 169 colorectal epithelial neoplasms representing various stages of carcinogenesis. The results were correlated with the morphologic characteristics of the neoplasms. There was no expression of CD10 in the stromal cells of normal colorectal tissue. CD10-positive stromal cells were present adjacent to the tumor cells in 16 of 73 adenomas with mild or moderate dysplasia. More frequent expression of CD10 by the stromal cells was detected in adenomas with severe dysplasia (12 of 17), intramucosal carcinomas (10 of 16), and invasive carcinomas (50 of 63) than in adenomas with mild or moderate dysplasia (P < 0.0001). Expression of CD10 by > 10% of the stromal cells was detected only within the area of the invasive growth front of invasive carcinomas, not in adenomas and in only 1 of the intramucosal carcinomas. The difference between invasive and non invasive tumors was significant (P < 0.0001). The stromal expression of CD10 was significantly associated with the accumulation of p53 and a larger tumor size.

These results indicate that CD10 expression is an integral part of colorectal carcinogenesis. CD10 expression seems to contribute to the invasion and thus probably facilitates metastasis.


The expression of E-cadherin and catenins in sporadic colorectal carcinoma

Mona A. El-Bahrawy, MBBCh
Richard Poulsom, PhD
Rosemary Jeffery
Ian Talbot, MD, FRCPath
Malcolm R. Alison, DSc

Hum Pathol 32:1216-1224. Abstract quote

The E-cadherin/catenin complex plays a major role in epithelial cell–cell adhesion. Immunohistochemical studies have highlighted perturbation in the expression and distribution of E-cadherin and catenins in sporadic colorectal neoplasms.

In this study, we compared the expression of E-cadherin and catenins (-, -, and -catenin) in 30 sporadic colorectal carcinomas with that in the adjacent nonneoplastic mucosa and assessed whether any perturbation in the level of expression occurred at the messenger RNA (mRNA) or protein level. We also compared the expression of E-cadherin and catenins in 13 lymph node deposits and the primary tumors. Immunohistochemistry was used to study the level of expression and cellular distribution of E-cadherin and catenins. Levels of mRNA were studied by in situ hybridization. E-cadherin and catenin immunoreactivity was increased with cytoplasmic accumulation in more than 85% of the neoplasms.

There were marked increases in the levels of mRNA in the carcinomas compared with the nonneoplastic mucosa. Nuclear localization of -catenin was higher at the invasive margin of some tumors, but expression of E-cadherin and catenin transcripts in the lymph node deposits showed no consistent relationship to that in the primary tumors.


Cyclin a correlates with carcinogenesis and metastasis, and p27 correlates with lymphatic invasion, in colorectal neoplasms.

Li JQ, Miki H, Wu F, Saoo K, Nishioka M, Ohmori M, Imaida K.

First Department of Pathology and the Third Department of Internal Medicine, Kagawa Medical University, Kagawa, Japan.


Hum Pathol 2002 Oct;33(10):1006-15 Abstract quote

Cyclin A binds to CDK2 and plays critical roles when cells proliferate; staining for Ki67 can monitor the proliferation. The cyclin A expression pattern remains unclear in colorectal carcinogenesis and remote metastasis, however, and no one has reported on the association of its expression with key clinicopathologic factors in primary cancer. p27(kip1) protein-an extremely important inhibitor of CDK2-seems unchanged as colorectal cancers metastasize to the lymph nodes, a result contrary to that seen in gastric and prostatic cancers.

To clarify the role of cyclin A in multistage colorectal neoplasms, cyclin A, CDK2, and Ki67 were immunohistochemically stained in 22 normal mucosa, 9 hyperplastic polyps, 61 adenomas, 197 primary carcinomas, 21 lymph node metastases, and 10 hepatic metastases. To clarify the alteration of p27(kip1) during lymphatic invasion, p27(kip1) was also stained in 21 primary cancers and paired lymph node foci. Situated in nuclei, cyclin A expression gradually increased from mild through moderate to severe dysplasia in adenomas and from normal tissue through hyperplasia to adenoma to early carcinoma. Expression was significantly decreased in the hepatic metastases and in the primary cancers showing venous invasion, deep infiltration, lymph node metastasis, mucinous type, advanced stage, or short postoperative survival time. Elevated cyclin A not only was linked with elevated CDK2 in primary cancers, but also was associated with increased Ki67 in both adenomas and primary carcinomas. Lymph node metastases lost more p27(kip1) than primary foci and hepatic lesions.

Thus, dysregulation of cyclin A and its control mechanisms may contribute to colorectal carcinogenesis; abatement of overexpression of cyclin A is associated with hepatic metastasis and cancerous invasion. Loss of p27(kip1) may promote lymph node metastasis.

Is Cytomegalovirus Associated With Human Colorectal Tumorigenesis?

Olaronke Akintola-Ogunremi, MD, Qing Luo, MD, Tong-Chuan He, MD, PhD, and Hanlin L. Wang, MD, PhD
Am J Clin Pathol 2005;123:244-249 Abstract quote

Despite the rapid advance in the understanding of molecular pathways underlying human colorectal tumorigenesis, the causes that initiate dysregulation of the pathways remain largely unknown. Human cytomegalovirus (CMV) has been implicated as a potential etiopathogenetic agent.

To further investigate whether CMV participates in human colorectal tumorigenesis, we examined 23 colorectal hyperplastic polyps, 65 colorectal adenomas, and 51 colorectal adenocarcinomas by immunohistochemical analysis using 2 antibody mixtures that recognize CMV immediate early, early, and delayed gene products. The results show that while typical nuclear staining (with or without cytoplasmic positivity) was observed in control cases of CMV colitis, no nuclear positivity was detected in any cases studied. Focal and weak cytoplasmic staining was noted in a subset of cases, particularly when a higher antibody concentration was used. This staining was believed to be nonspecific, however, because it also was observed in normal-appearing colonic mucosa. In addition, polymerase chain reaction failed to detect the presence of CMV DNA in 24 selected cases showing nonspecific cytoplasmic immunostaining.

These observations demonstrate an absence of CMV proteins and DNA in human colorectal adenocarcinomas and their precursor lesions.
The mismatch repair protein status of colorectal small cell neuroendocrine carcinomas.

Robert E. Fechner Surgical Pathology Laboratory, University of Virginia, Charlottesville, VA.


Am J Surg Pathol. 2006 Nov;30(11):1401-4 Abstract quote

Small cell neuroendocrine carcinoma (SCNC) of the colorectum is a rare and highly aggressive malignancy. It can be associated with conventional-type adenocarcinoma, and an overlying adenoma can often be identified. A disproportionate number has been noted to arise in the right colon. Although some phenotypes (eg, mucinous adenocarcinoma) have been shown to be associated with deficient mismatch repair (MMR) and thus microsatellite instability (MSI), the MMR protein status of colorectal SCNCs has not been investigated.

This study investigated the status of 3 MMR proteins, hMLH1, hMSH2, and hMSH6, in SCNCs of the colorectum. Fifteen SCNCs were identified on the basis of previous descriptions and the World Health Organization histologic criteria for the diagnosis of pulmonary small cell carcinoma and immunohistochemical evidence of epithelial and neuroendocrine differentiation. Patient age and sex and tumor size and location were recorded. Immunohistochemistry was performed with antibodies to pancytokeratin (cocktail), CD56, neuron specific enolase, synaptophysin, chromogranin, hMLH1, hMSH2, and hMSH6.

Patients' ages ranged from 44 to 87 years (mean age=73 y) and there were 9 men and 6 women. Tumors were located in the right colon (6), sigmoid colon (4), and rectum (3) (the locations of 2 cases were not recorded) and ranged in size from 0.4 to 15 cm in greatest dimension (mean=6.6 cm). All tumors showed immunoreactivity with antibodies to pancytokeratin and with antibodies to at least 1 neuroendocrine antigen. MMR proteins were intact by immunohistochemistry in all but a single case that had neither an identifiable precursor lesion nor positive internal control (hMLH1 loss). Colorectal SCNCs are rare and are often right-sided. They are aggressive and tend to occur in older individuals. Most colorectal SCNCs have intact MMR proteins, suggesting that they develop secondary to chromosomal instability rather than MSI.

Our single case showing potential MMR protein loss suggests that this phenotype may be independent of the developmental pathway (ie, chromosomal instability vs. MSI). This may explain the rare cases of SCNC that have been identified in patients with hereditary nonpolyposis colon cancer.
Value of Immunohistochemical Detection of DNA Mismatch Repair Proteins in Predicting Germline Mutation in Hereditary Colorectal Neoplasms.

Shia J, Klimstra DS, Nafa K, Offit K, Guillem JG, Markowitz AJ, Gerald WL, Ellis NA.

From the Departments of *Pathology, daggerMedicine, and double daggerSurgery, Memorial Sloan-Kettering, Cancer Center, New York, NY.
Am J Surg Pathol. 2005 Jan;29(1):96-104. Abstract quote  

The utility of immunohistochemistry (IHC) as a screening method for the identification of persons with mutations in the DNA mismatch repair (MMR) genes in hereditary nonpolyposis colorectal cancer (HNPCC) remains to be defined.

In this study, we analyzed the value of IHC versus that of microsatellite instability (MSI) testing in predicting mutation status of the MLH1, MSH2, and MSH6 genes in colorectal carcinomas and adenomas, and explored the frequency and significance of immunohistochemical staining variability. The study samples included 83 carcinomas and 29 adenomas derived from 110 patients who had strong family histories of colorectal cancer.

Our results showed that IHC correctly predicted MSI status in 76% of the cases with a specificity of 100%. The overall sensitivity of IHC in predicting a germline mutation was 79% (30 of 38) with a specificity of 89% (48 of 54), whereas that of MSI testing was 97% (30 of 31) with a specificity of 83% (35 of 42). Six of 31 analyzable cases that had a disease-causing mutation and exhibited MSI showed normal IHC. The lower sensitivity of IHC was caused mainly by its low sensitivity in detecting MLH1 gene mutation (4 of 9). Coexisting adenomas and carcinomas observed in the same slide (n = 12) showed a similar or identical staining pattern for all three proteins. No significant difference was detected in the sensitivity of IHC or MSI in detecting a germline mutation between isolated adenomas and carcinomas. In IHC-positive cases, heterogeneous staining was noted in 30% to 40% of the cases with the three different antibodies, and cytoplasmic staining in 5% to 13%. Weak IHC (defined as positive staining in <10% of the tumor with weak intensity) was noted in 14 tumors: 5 for the MLH1 antibody, 1 for MSH2, and 8 for MSH6. One of the 5 MLH1 cases exhibited MSI and had an MLH1 germline mutation. Five of the 8 MSH6 cases exhibited MSI and had MSH2 germline mutations.

In conclusion, our study shows that 1) IHC identifies a significant portion of colorectal tumors derived from MMR gene germline mutation carriers and can be used as an adjunct measure in the identification of HNPCC families, but IHC cannot replace MSI testing; 2) adenomas have similar MMR protein expression patterns as carcinomas and may serve as an adequate sample for screening purposes in the identification of patients with MMR mutations; 3) not all IHC-positive cases show uniform positivity throughout the tumor; and 4) weak and focal staining of an MMR protein may be associated with MSI or gene mutation or both, suggesting the need to incorporate staining intensity in further IHC studies.
What Is the Best Way to Assess Microsatellite Instability Status in Colorectal Cancer?: Study on a Population Base of 462 Colorectal Cancers.

Chapusot C, Martin L, Puig PL, Ponnelle T, Cheynel N, Bouvier AM, Rageot D, Roignot P, Rat P, Faivre J, Piard F.

From *Service d'Anatomie Pathologique, Dijon, Faculte de Medecine, Dijon; daggerINSERM EMI 0106-IFR 100, Faculte de Medecine, Dijon; double daggerHopital europeen Georges Pompidou Assistance Publique Hopitaux de Paris, Paris; section signU490 Laboratoire de Toxicologie Moleculaire, Paris; and paragraph signCentre de Pathologie de Dijon, Dijon, France.
Am J Surg Pathol. 2004 Dec;28(12):1553-1559. Abstract quote  

The assessment of the microsatellite instability (MSI) status in colorectal cancers is presently warranted for three reasons: 1) as a screening tool for hereditary nonpolyposis colorectal cancer, 2) as a prognostic marker, and 3) as a potential predictive factor of chemotherapy response.

The aim of this study was to evaluate, on a large scale with tissue samples coming from a number of different sources, the difficulties met with routine use of immunohistochemistry (IHC) and to determine if it really does offer an accurate alternative to PCR genotyping. Colorectal carcinomas from 462 consecutive patients resected in public or private hospitals were assessed for MSI status by two methods: MSI testing (with BAT-26 microsatellite) and IHC detection of hMLH1, hMSH2, and hMSH6 proteins. Of the 398 cancers tested, immunohistochemistry was noncontributory in 42 (10.5%), focal in 9 (2.3%), and discordant with the PCR results in 36 (9%). For these 87 cases, complementary analyses were performed to explain discrepancy. After additional IHC assay with modified processing protocols, 8 cases remained noncontributory, 2 focal, and 28 discordant: 18 microsatellite stability IHC/MSI PCR and 10 MSI IHC/microsatellite stability PCR. For these discordant cases, we performed a multiplex PCR assay on DNA extracted from the frozen sample and BAT-26 was amplified from DNA extracted from the paraffin blocks used for IHC. Four discordant cases were reclassified after PCR multiplex assay (3 as MSI and 1 as microsatellite stability). Five other cases displayed intratumoral heterogeneity and 19 remained discordant. The discrepancy could be partly explained by variable technical protocols of fixation in the different laboratories, leading to variations in staining quality and difficulties in IHC interpretation.

This population-based study is the first one to show that IHC is not sensitive and specific enough to be used routinely. Immunohistochemistry analysis of MMR proteins must be performed in standardized conditions and interpreted by confirmed pathologists. It cannot replace PCR as long as protocols are not optimized and harmonized.

Value of histopathology in predicting microsatellite instability in hereditary nonpolyposis colorectal cancer and sporadic colorectal cancer.

Shia J, Ellis NA, Paty PB, Nash GM, Qin J, Offit K, Zhang XM, Markowitz AJ, Nafa K, Guillem JG, Wong WD, Gerald WL, Klimstra DS.

Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY 10002, USA.

Am J Surg Pathol. 2003 Nov;27(11):1407-17. Abstract quote  

Identification of colorectal carcinomas with high levels of DNA microsatellite instability (MSI-H) is important because of the suggested prognostic and therapeutic significance associated with MSI.

The role of histology in identifying MSI-H colorectal carcinomas has been suggested by some studies but not confirmed by others. Furthermore, previous studies assumed that hereditary nonpolyposis colorectal cancer (HNPCC)-associated MSI-H tumors and sporadic MSI-H tumors have similar histology. This assumption, however, has been challenged by more recent studies.

In this report, we first analyzed the value of various histologic features in predicting MSI-H in a series of 218 colorectal carcinomas containing mixed HNPCC and sporadic cases [77 tumors (35%) were MSI-H by polymerase chain reaction (PCR) method]. Then, we evaluated the various histologic features comparatively in two groups extracted from the 218 cases. Group A was composed of 84 tumors from 82 patients obtained based on a strong family history (HNPCC/HNPCC-like group) (male to female ratio, 42:40; age range, 23-80 years, median, 53.5 years). Thirty-one of the 84 tumors (41.7%) were MSI-H by PCR, and all 31 cases were HNPCC by Amsterdam criteria. Group B was composed of 109 patients with no family history of colorectal cancer or HNPCC-associated cancer, obtained from surgical clinics (sporadic group) (male to female ratio, 65:69; age range, 31-84 years, median, 65 years). Thirty-five of the 109 tumors (32.1%) were MSI-H by PCR.

Our results showed that, overall, poor tumor differentiation, medullary type, mucinous type, signet-ring cell component, histologic heterogeneity, and increased tumor-infiltrating lymphocytes (TILs) were features more commonly seen in MSI-H tumors than in non-MSI-H tumors. Comparative analyses showed that the overall TIL count was significantly higher in HNPCC/HNPCC-like group, and mucinous type appeared to be more frequent in HNPCC MSI-H tumors than in sporadic MSI-H tumors. However, there was no significant difference in the odds ratio for predicting MSI-H status for any of the analyzed histologic features between HNPCC/HNPCC-like group and sporadic group, indicating that differences between HNPCC and sporadic MSI-H tumors did not significantly impact on the informative value of histology in predicting MSI in the two different clinical settings. TIL counts followed by histologic heterogeneity provided the greatest sensitivity and specificity in predicting MSI status in both HNPCC/HNPCC-like and sporadic cases.

Using a stepwise logistic regression model, a formula was generated that could be used to calculate the probability of a colorectal carcinoma being MSI-H based on morphologic features.

Histopathology and mismatch repair status of 458 consecutive colorectal carcinomas.

Wright CL, Stewart ID.

Surgical Pathology Unit, North Shore Hospital, Takapuna, Auckland, New Zealand.
Am J Surg Pathol. 2003 Nov;27(11):1393-406. Abstract quote  

Defects in the mismatch repair (MMR) genes hMLH1 and hMSH2 have been found in 10% to 20% of sporadic colorectal carcinomas and also many cases of hereditary nonpolyposis colorectal cancer syndrome. Patients with these tumors have an improved prognosis and may show greater sensitivity to chemotherapy.

We examined 458 resected colorectal carcinomas from 430 consecutive patients and used immunohistochemistry to determine which tumors lacked expression of these genes (MMR-d). We correlated the status of MMR-d or "intact" expression with stage, site, and histology. Eighty-nine of 458 tumors (19.4%) were MMR-d, including 80 hMLH1 and 9 hMSH2 tumors. A total of 6% of patients had synchronous tumors, and 37.7% of these were MMR-d (P=0.0008). A high proportion of patients with previous breast cancer (4 of 6 patients) had hMLH1-defective colorectal carcinomas. MMR-d tumors presented at an earlier stage than intact tumors, and the node-positive MMR-d tumors were less likely than intact tumors to have pericolonic extranodal tumor deposits (18.2% vs. 44%). The proportion of tumors at each site that were MMR-d increased progressively from cecum (32%) to ascending (35%) to transverse colon, where 41% of all tumors were defective.

The proportions then rapidly decreased, reaching the lowest rate (4.7%) in the rectum. Both types of MMR-d tumors more often had expansive borders, intraepithelial lymphocytosis, peritumoral lymphoid, and Crohn's-like lymphoid responses than the intact tumors; the frequencies of these features diminished with advancing stage. Tumor budding was less common in stage II and III MMR-d tumors than in intact tumors. Keloid and myxoid type stromas correlated with stage and vascular invasion and were not related to mismatch repair status. Significant differences existed between the hMLH1 and hMSH2 tumors. The reported right-sided preponderance of MMR-d tumors is due to most hMLH1, but not hMSH2, tumors being found there (87.5% vs. 44.4%). hMSH2 tumors were most common in the rectum (55.6%). Mucinous tumors were common in hMLH1 tumors (36.3%) but not in hMSH2 tumors (11.1%). hMLH1 tumors were most likely to be poorly differentiated (70%), which was uncommon with hMSH2 tumors (22.2%). hMSH2 tumors were more likely to be confined to the wall (66.7%) than hMLH1 (20%) or intact tumors (23%).

We conclude that hMLH1 and hMSH2-defective tumors have distinctly differing histologic features from each other.

Microsatellite Instability in Double Primary Cancers of the Colorectum and Stomach

Hee Sung Kim, M.D., Ph.D., Nam Bok Cho, M.D., Ph.D., Jae Hyung Yoo, M.D., Ph.D., Ki-Hyuk Shin, Ph.D., Jae-Gahb Park, M.D., Ph.D., Yong Il Kim, M.D., Ph.D. and Woo Ho Kim, M.D., Ph.D.

Department of Pathology (HSK, YIK, WHK) and Surgery (JGP) and Cancer Research Institute (KHS, JGP, WHK), Seoul National University College of Medicine, Seoul, Korea; and Department of Pathology (NBC, JHY), Chung-Ang University College of Medicine, Seoul, Korea

Mod Pathol 2001;14:543-548 Abstract quote

Little is known about genetic alterations of patients who present multiple primary cancers. We hypothesized that microsatellite instability (MSI) is one of the underlying genetic factors in the development of double primary cancers in colorectal cancer patients.

We examined for MSI in 41 colorectal cancer patients who presented with extra-colonic primary cancers consisted of 17 gastric and 24 non-gastric cancers.

Coincident MSI+ in tumors of two organs were observed in 3 (17.7%) of 17 patients with colon and stomach cancers and 0 of 24 patients with colon and non-gastric cancers (P = .03). In 17 patients with colon and stomach cancers, 6 (31.6%) of 19 colon cancers and 3 (17.7%) of 17 gastric cancers exhibited MSI+. Among four patients with metachronous colon cancers who were identified within the 41 double primary cancer patients, two patients were associated with the MSI+ phenotype.

In summary, the prevalent coincidence of MSI suggests that genetic defect of mismatch repair deficiency may be responsible for a small subset of double primary cancers of the colorectum and stomach.

Detection of Microsatellite Instability From Archival, Hematoxylin-Eosin–Stained Colorectal Cancer Specimen

Joerg Trojan, MD, Jochen Raedle, MD, Guenter Herrmann, MD, Angela Brieger, PhD, and Stefan Zeuzem, MD

From the Second Department of Internal Medicine, Johann Wolfgang Goethe-University, Frankfurt, Germany (Drs Trojan, Raedle, Brieger, and Zeuzem); and the Department of Pathology, Klinikum Ludwigsburg, Ludwigsburg, Germany (Dr Herrmann)

Arch Pathol Lab Med 2002;Vol. 126, No. 2, pp. 202–204 Abstract quote

Microsatellite instability (MSI) is characteristic of hereditary nonpolyposis colorectal cancer (HNPCC). Owing to early onset of colorectal cancer before the age of 50 years and/or familial clustering of HNPCC-related malignancies, the diagnosis of HNPCC was suspected in 2 patients.

Because no paraffin-embedded tumor tissue was available, we used archival 5-m, hematoxylin-eosin–stained tumor specimen slides for direct MSI analysis. Tissue was microdissected and cells were lysed using 1% Triton. Fluorescence polymerase chain reaction amplification of a panel of 7 microsatellite markers, including all markers of the current international reference panel (BAT-25, BAT-26, D2S123, D5S346, and D17S250), demonstrated MSI in one patient and excluded MSI in the other.

In conclusion, this study demonstrates the feasibility of MSI analysis by direct fluorescence polymerase chain reaction amplification using hematoxylin-eosin–stained tissue specimens without the need for prior DNA extraction.

Immunohistochemical Pattern of MLH1/MSH2 Expression Is Related to Clinical and Pathological Features in Colorectal Adenocarcinomas with Microsatellite Instability.

Lanza G, Gafa R, Maestri I, Santini A, Matteuzzi M, Cavazzini L.

Department of Experimental and Diagnostic Medicine, Section of Anatomic Pathology, University of Ferrara (GL, RG, IM, MM, LC).


Mod Pathol 2002 Jul;15(7):741-9 Abstract quote

Detection of colorectal carcinomas with high-frequency microsatellite instability (MSI-H) is clinically important for several reasons. Recent studies suggested that immunohistochemical analysis of MLH1 and MSH2 expression is a rapid and accurate method for identifying large bowel tumors of the MSI-H phenotype.

In this study, we evaluated by immunohistochemistry MLH1 and MSH2 protein expression in 132 MSI-H, 23 MSI-L (low-frequency MSI), and 150 microsatellite stable (MSS) colorectal adenocarcinomas. Loss of MLH1 or MSH2 expression was detected in 120 (90.9%) MSI-H carcinomas, whereas all MSI-L and MSS tumors showed normal expression of both proteins. Lack of MLH1 nuclear staining was observed much more often than absence of MSH2 nuclear staining (106 and 14 cases, respectively). Among MSI-H carcinomas, MLH1/MSH2 pattern of expression was significantly related to several clinical and pathological variables. In particular, MSI-H MLH1/MSH2-positive carcinomas were more often located in the distal colon, were more frequently classified as ordinary adenocarcinomas, and were more likely to be well or moderately differentiated, p53 positive, and <7 cm in diameter than were MLH1-negative and MSH2-negative carcinomas. In addition, MLH1-negative carcinomas were less common among patients with hereditary nonpolyposis colorectal cancer (HNPCC) or suspected HNPCC and in the group of patients aged <50 years. Patients with MLH1-negative carcinomas more frequently died of disease than did patients with MLH1/MSH2-positive and MSH2-negative MSI-H tumors, but the difference was not statistically significant.

The results of the present investigation strongly indicate that immunohistochemical analysis of MLH1 and MSH2 expression is a practical and reliable method for the routine detection of the vast majority of MSI-H large bowel adenocarcinomas. Our data also point out that MSI-H MLH1/MSH2-positive colorectal carcinomas are characterized by distinctive pathological features.

Leading-Edge Myofibroblasts in Human Colon Cancer Express Plasminogen Activator Inhibitor-1

Martin Illemann, MSc, etal.
Am J Clin Pathol 2004;122:256-265 Abstract quote

Plasminogen activator inhibitor-1 (PAI-1) is up-regulated strongly in various cancer tissues, including colon cancer tissue. Highly specific rabbit polyclonal antibodies against PAI-1 were used for immunohistochemical localization of PAI-1 in 12 invasive colorectal adenocarcinomas. PAI-1 immunoreactivity was observed in endothelial cells of some vessels located in the submucosa and in several fibroblast-like cells located at the invasive front. No PAI-1 immunoreactivity was seen in cancer cells in any of the 12 cases.

Double immunofluorescence using the PAI-1 antibodies together with antibodies against a-smooth muscle actin for myofibroblast/smooth muscle cells and CD34 for endothelial cells showed that more than 80% of the PAI-1–positive fibroblast-like cells in all 12 cases were myofibroblasts. In 4 of 12 cases, a few of the PAI-1–positive fibroblast-like cells in the invasive front were CD34+.

We conclude that the majority of PAI-1–positive fibroblast-like cells located at the leading edge of the invasive colon cancers are myofibroblasts.



Screening men for prostate and colorectal cancer in the United States: does practice reflect the evidence?

Sirovich BE, Schwartz LM, Woloshin S.

VA Outcomes Group, 111B, Department of Veterans Affairs Medical Center, White River Junction, VT 05009.

JAMA 2003 Mar 19;289(11):1414-20 Abstract quote

CONTEXT: The debate about the efficacy of prostate-specific antigen (PSA) screening for prostate cancer has received substantial attention in the medical literature and the media, but the extent to which men are actually screened is unknown. If practice were evidence-based, PSA screening would be less common among men than colorectal cancer screening, a preventive service of broad acceptance and proven efficacy.

OBJECTIVE: To compare the prevalences of PSA and colorectal cancer screening among US men.

DESIGN, SETTING, AND POPULATION: The 2001 Behavioral Risk Factor Surveillance System, an annual population-based telephone survey of US adults conducted by the Centers for Disease Control and Prevention, was used to gather data on a representative sample of men aged 40 years or older from all 50 states and the District of Columbia (n = 49 315).

MAIN OUTCOME MEASURES: Proportions of men ever screened and up to date on screening for prostate cancer (with PSA testing) and colorectal cancer (with fecal occult blood testing, flexible sigmoidoscopy, or colonoscopy).

RESULTS: Overall, men are more likely to report having ever been screened for prostate cancer than for colorectal cancer; 75% of those aged 50 years or older have had a PSA test vs 63% for any colorectal cancer test (risk ratio [RR], 1.20; 95% confidence interval [CI], 1.18-1.21). Up-to-date PSA screening is also more common than colorectal cancer screening for men of all ages. Among men aged 50 to 69 years (those for whom there is the greatest consensus in favor of screening), 54% reported an up-to-date PSA screen, while 45% reported up-to-date testing for colorectal cancer (RR, 1.19; 95% CI, 1.16-1.21). In state-level analyses of this age group, men were significantly more likely to be up to date on prostate cancer screening compared with colorectal cancer screening in 27 states, while up-to-date colorectal cancer screening was more common in only 1 state.

CONCLUSION: Among men in the United States, prostate cancer screening is more common than colorectal cancer screening. Physicians should ensure that men who choose to be screened for cancer are aware of the known mortality benefit of colorectal cancer screening and the uncertain benefits of screening for prostate cancer.


Detection of APC mutations in fecal DNA from patients with colorectal tumors.

Traverso G, Shuber A, Levin B, Johnson C, Olsson L, Schoetz DJ Jr, Hamilton SR, Boynton K, Kinzler KW, Vogelstein B.

Graduate Program in Human Genetics, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Johns Hopkins School of Medicine, Baltimore, USA.

N Engl J Med 2002 Jan 31;346(5):311-20 Abstract quote

BACKGROUND: Noninvasive methods for detecting colorectal tumors have the potential to reduce morbidity and mortality from this disease. The mutations in the adenomatous polyposis coli (APC) gene that initiate colorectal tumors theoretically provide an optimal marker for detecting colorectal tumors. The purpose of our study was to determine the feasibility of detecting APC mutations in fecal DNA with the use of newly developed methods.

METHODS: We purified DNA from routinely collected stool samples and screened for APC mutations with the use of a novel approach called digital protein truncation. Many different mutations could potentially be identified in a sensitive and specific manner with this technique.

RESULTS: Stool samples from 28 patients with nonmetastatic colorectal cancers, 18 patients with adenomas that were at least 1 cm in diameter, and 28 control patients without neoplastic disease were studied. APC mutations were identified in 26 of the 46 patients with neoplasia (57 percent; 95 percent confidence interval, 41 to 71 percent) and in none of the 28 control patients (0 percent; 95 percent confidence interval, 0 to 12 percent; P<0.001). In the patients with positive tests, mutant APC genes made up 0.4 to 14.1 percent of all APC genes in the stool.

CONCLUSIONS: APC mutations can be detected in fecal DNA from patients with relatively early colorectal tumors. This feasibility study suggests a new approach for the early detection of colorectal neoplasms.

Detection of proximal colorectal cancers through analysis of faecal DNA.

Traverso G, Shuber A, Olsson L, Levin B, Johnson C, Hamilton SR, Boynton K, Kinzler KW, Vogelstein B.

Lancet 2002 Feb 2;359(9304):403-4 Abstract quote

Detection of mutations in faecal DNA represents a promising, non-invasive approach for detecting colorectal cancers in average-risk populations. One of the first practical applications of this technology involves the examination of microsatellite markers in sporadic cancers with mismatch-repair deficiencies. Since such cancers nearly always occur in the proximal colon, this test might be useful as an adjunct to sigmoidoscopy, which detects only distal colorectal lesions.

We report here the first in-depth analysis of faecal DNA from patients with proximal cancers to determine the feasibility, sensitivity, and specificity of this approach. Using a sensitive method for microsatellite mutation detection, we found that 18 of 46 cancers had microsatellite alterations and that identical mutations could be identified in the faecal DNA of 17 of these 18 cases.


Circulating p53 antibody in patients with colorectal cancer: relation to clinicopathologic features and survival.

Shiota G, Ishida M, Noguchi N, Oyama K, Takano Y, Okubo M, Katayama S, Tomie Y, Harada K, Hori K, Ashida K, Kishimoto Y, Hosoda A, Suou T, Kanbe T, Tanaka K, Nosaka K, Tanida O, Kojo H, Miura K, Ito H, Kaibara N, Kawasaki H.

Second Department of Internal Medicine, Tottori University School of Medicine, Yonago, Japan.

Dig Dis Sci 2000 Jan;45(1):122-8 Abstract quote

The presence of serum anti-p53 antibody has been reported to be associated with survival of patients with breast cancer, ovarian cancer, and hepatocellular carcinoma. To clarify prognostic significance of p53 antibody in colorectal cancer, serum p53 antibody was measured in patients with colorectal cancer.

The 89 patients included 71 with colorectal cancer and 18 with colon polyp. An enzyme-linked immunosorbent assay was used to detect p53 antibodies in serum. Clinicopathological parameters such as age, sex, degree of differentiation of cancer, location of tumor, liver metastasis, stage classification, Dukes classification, CEA, CA19-9, and immunostaining of p53 and anti-p53 antibody were evaluated as prognostic factors of colorectal cancer. p53 antibody was positive in 18 of 71 (25%) with colorectal cancer, whereas it was positive in only 1 of 18 (6%) with colon polyp. The patients with p53 antibody had higher CEA and CA19-9 levels, higher positive rates of p53 protein expression in cancer cells, and higher liver metastasis rates. The p53 antibody positivity at stage classification I-IIIb/ Dukes classification A-C was significantly lower than that at stage classification IV/Dukes classification D.

Overall survival in colorectal cancer patients with p53 antibody was significantly shorter than in those without p53 antibody. A Cox regression analysis showed that liver metastasis, stage classification, Dukes classification, CA19-9, and p53 antibody were significant prognostic factors in colorectal cancer. Serum anti-p53 antibody could serve as one of the prognostic factors in patients with colorectal cancer.


General description Right sided lesions tend to be polypoid exophytic masses
Left sided lesions are usually annular lesions producing a characteristic napkin ring lesion in the bowel

Lymph node recovery from colorectal resection specimens removed for adenocarcinoma. Trends over time and a recommendation for a minimum number of lymph nodes to be recovered.

Goldstein NS, Sanford W, Coffey M, Layfield LJ.

Department of Anatomic Pathology, William Beaumont Hospital, Royal Oak, Michigan 48073, USA.

Am J Clin Pathol 1996 Aug;106(2):209-16 Abstract quote

Recovery of pericolorectal lymph nodes from colectomy specimens has long been part of colorectal cancer staging. Recently, adjuvant therapy has been added for high stage carcinomas, providing further impetus for performing careful lymph node dissections. Pericolorectal lymph nodes were examined to determine if there has been a change over time in the number of lymph nodes recovered and proportion of specimens with pericolonic lymph node metastases from colorectal carcinoma resection specimens. Also, the authors attempted to establish a recommendation for a minimum number of lymph nodes that should be recovered before a colon can be considered free of metastases.

Slides and reports of the first 20 consecutive pT3 colorectal carcinoma resections in each year from 1955 to 1995 at William Beaumont Hospital that did not have known metastases at the time of surgery were reviewed (750 specimens total). The mean number of lymph nodes recovered per specimen and incidence of detected lymph node metastases increased over the 41-year period, with the greatest increase occurring during 1992-1995. The greatest proportion of patients with lymph node metastases detected occurred in the 17 to 20 lymph nodes recovered per specimen group. Specimens with more than 20 lymph nodes did not have a higher proportion of lymph node metastases detected compared to specimens with 17 to 20 lymph nodes. Approximately 20% of the specimens with metastases had more than 17 lymph nodes recovered.

These results suggest that pathologists should retrieve all the lymph nodes that can be recovered, but at least 17 lymph nodes should be recovered to insure accurate documentation of nodal metastases when present.

Disparate surgical margin lengths of colorectal resection specimens between in vivo and in vitro measurements. The effects of surgical resection and formalin fixation on organ shrinkage.

Goldstein NS, Soman A, Sacksner J.

Department of Anatomic Pathology, William Beaumont Hospital, Royal Oak, Michigan 48073, USA

Am J Clin Pathol 1999 Mar;111(3):349-51 Abstract quote

We noticed almost routine disparate results in margin lengths when colorectal specimens are measured in vivo by the surgeon and in vitro by the pathologist.

We studied 26 sigmoid and rectum specimens to document the amount of organ shrinkage after surgical removal and fixation. Each specimen had a 5.0-cm segment at each end of the specimen marked by serosal sutures before vascular devitalization. The segments were measured after the specimen sat unfixed for 10 to 20 minutes and after 12 to 18 hours of formalin fixation. The segments shrank to a median length of 3.0 cm (40% of the in vivo length) after 10 to 20 minutes and an additional 0.85 cm, to a median length of 2.15 cm, after fixation. Overall after fixation, the segments shrank 57% of the in vivo length. Approximately 70% of the shrinkage occurred during the first 10 to 20 minutes after removal, and the remaining 30% occurred after fixation.

For optimal accuracy, margin distance must be obtained immediately after surgical removal. Once the specimen has been removed for several minutes, the difference between unfixed and fixed margin lengths is 30%. A correction factor of approximately 2x should be applied when interpreting the margin length.

Cecum and ascending colon 38%
Transverse colon 18%
Descending colon 8%
Sigmoid colon 35%
Multiple sites 1%


Clinicopathologic and Immunohistochemical Study of Small Apparently "De Novo" Colorectal Adenocarcinomas.

*Department of Pathology, Brigham and Women's Hospital, Harvard Medical School daggerSection of Gastroenterology, Boston Medical Center, Boston University School of Medicine, Boston, MA.


Am J Surg Pathol. 2007 Feb;31(2):207-215. Abstract quote

Rarely, adenocarcinomas of the colorectum develop as small (</=1.0 cm) rapidly invasive tumors without an obvious adenomatous or "in situ" component. These tumors have been termed "de novo" carcinomas. Although it is believed by some that these tumors are more aggressive than conventional large adenocarcinomas with an identifiable in situ component, little is known about the biologic characteristics and natural history of these lesions.

The aim of this study was to evaluate and compare the pathologic features, biologic characteristics, and natural history of small apparently de novo invasive colorectal adenocarcinomas with conventional large (>1.0 cm) carcinomas. Routinely processed specimens from 20 patients (M/F ratio: 13/7; mean age: 65 y) with small apparently de novo invasive colorectal adenocarcinomas (all </=1.0 cm in size) were evaluated for a variety of clinical and pathologic features. In addition, immunostains for p53, beta-catenin, DPC4, hMLH1, hMSH2, and MGMT were evaluated in all cases.

The findings in this group of cases were compared with those from 20 control patients (M/F ratio: 8/12; mean age: 60 y) with stage-matched conventional "large" colorectal adenocarcinomas (all >1.0 cm in size). Patients were followed for a mean of 52.6 and 60.6 months, respectively, for the 2 groups. Small apparently de novo invasive adenocarcinomas were present in the left colon, transverse colon, and right colon in 85%, 10%, and 5% of cases, respectively. Their mean size was 7 mm (range: 3 to 10 mm). All cases were stage T1 and the majority were moderately differentiated (75%). Only 1 (5%) patient had lymph node metastases. Two (10%) cases were mucinous and only 1 (5%) showed prominent tumor infiltrating lymphocytes. Upon complete sectioning of the tissue blocks of tumor, residual foci of adenomatous epithelium were present in 16/20 (80%) cases, of which 75% contained foci of high-grade dysplasia. P53 and nuclear beta-catenin staining was present in 70% and 85% of cases, respectively, but only 5 cases (25%) showed loss of DPC4. Loss of MGMT expression was seen in 5 cases (25%), loss of hMSH2 in only 1 case (5%), and none showed loss of hMLH1. Only 2 patients (10%) developed visceral metastases upon follow-up. Control patients had similar demographic features, clinical outcome, anatomic distribution of tumors, degree of differentiation, and prevalence of positivity for the immunostains noted above, to the study cases.

In our patient population, true small de novo colorectal adenocarcinomas, tumors that lack an identifiable adenomatous component, are exceedingly rare, because complete tissue sectioning reveals residual adenomatous tissue in the majority of cases. The biologic characteristics and natural history of small carcinomas with a minimal dysplastic component, and those with no identifiable adenomatous component, are similar to conventional large (>1 cm) adenocarcinomas, and, thus, they should probably be treated similarly.

Accuracy of pathologic interpretation of colorectal polyps by general pathologists in community practice.

Rex DK, Alikhan M, Cummings O, Ulbright TM.

Departments of Medicine, Gastroenterology, and Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA.

Gastrointest Endosc 1999 Oct;50(4):468-74 Abstract quote

BACKGROUND: The histologic features of colorectal polyps often guide colonoscopic surveillance and the need for surgical intervention. Our objective was to evaluate the pathologic interpretation of colorectal polyps by general pathologists in community practice.

METHODS: Twenty histologic slides of colorectal polyps were reviewed by 20 randomly selected general pathologists in community practice. There were 5 malignant polyps, 9 adenomas, and 6 miscellaneous polyps.

RESULTS: Cancer was correctly identified in 91% of readings and adenoma in 94%. The grade of differentiation of cancer was provided in 55% of readings, and comment regarding whether the resection margin was free of cancer was made by 50% of pathologists. Tubular adenoma was called tubulovillous or villous in 35% of readings, but tubulovillous or villous adenoma was seldom (2%) called tubular. High-grade dysplasia was correctly identified in 47% of 60 readings, was called invasive cancer in 22%, and was missed in 31%. Among miscellaneous polyps, hyperplastic polyp was correctly recognized in 75% of cases, and inflammatory polyp and juvenile polyp each were recognized by 16 of 20 pathologists (80%). Peutz-Jeghers hamartoma was identified by 4 of 20 pathologists (20%), and the polypoid phase of solitary rectal ulcer syndrome was recognized by 2 pathologists (10%).

CONCLUSION: Areas of strength with regard to interpretation of colon polyps by general pathologists in community practice included identification of cancer, adenoma, and certain non-neoplastic polyps (e.g., inflammatory and juvenile polyps). Areas of weakness included lack of comment on cancer differentiation and proximity to the resection line, erroneous identification of high-grade dysplasia, and identification of rare lesions. The results of this study suggest areas on which to focus continuing education and continuous quality improvement efforts with regard to polyp interpretation.

Usual type Raggedly infiltrating glands lined by pleomorphic columnar cells
A prominent desmoplastic stromal host response is often elicited by the infiltrating tumor
ADENOSQUAMOUS Malignant gland mixed with squamous cell carcinoma

Stromal eosinophilia in colonic epithelial neoplasms.

Moezzi J, Gopalswamy N, Haas RJ Jr, Markert RJ, Suryaprasad S, Bhutani MS.

Department of Veterans Affairs Medical Center, and Wright State University School of Medicine, Dayton, Ohio 45428, USA

Am J Gastroenterol 2000 Feb;95(2):520-3 Abstract quote

OBJECTIVE: The purpose of this retrospective study was to determine the frequency and intensity of eosinophilic infiltration (or tissue eosinophilia) in the stroma of colonic adenomas, hyperplastic polyps, and colorectal adenocarcinomas. Eosinophilic infiltration in various malignancies has been reported but has not been evaluated in benign colorectal adenomas and hyperplastic polyps.

METHODS: We analyzed 488 colonic neoplasms: 176 tubular adenomas, 55 tubulovillous adenomas, 82 villous adenomas, 15 early carcinomas in polyps, 95 invasive adenocarcinomas, and 65 hyperplastic polyps for the presence of eosinophilic infiltration. The eosinophilic infiltration was graded as negative (< or =5%), mild to moderate (>5-40%), or marked (>40%), depending on the percentage of eosinophils relative to total inflammatory cells in the stroma.

RESULTS: Mild to moderate eosinophilia was noted in 75% of all adenomas. The transitional zone in all cases of invasive adenocarcinoma (zone between normal tissue and adenocarcinoma) revealed a high percentage of tissue eosinophilia. There was a striking absence of TE in the stroma of invasive adenocarcinomas. Only 5% of hyperplastic polyps had any eosinophilic infiltration.

CONCLUSIONS: These data suggest that, in the spectrum of colonic neoplasms, stromal eosinophilia is most prominent in adenomas and seems to decrease with progression through the adenoma-carcinoma sequence. The ramifications of this study may alter management plans and provide some prognostic information for clinical evaluation.

Flat and polypoid adenocarcinomas of the colorectum: A comparative histomorphologic analysis of 47 cases.

Nasir A, Boulware D, Kaiser HE, Bodey B, Siegel S, Crawley S, Yeatman T, Marcet JE, Coppola D.
Hum Pathol. 2004 May;35(5):604-11. Abstract quote  

"Flat" colorectal adenomas and adenocarcinomas are well documented in the Japanese literature but only sporadically reported in the English literature.

The present study involved systematic morphological analysis of a large series of colorectal carcinomas (CRCs) to determine the frequency of these "flat" CRCs (FCRCs) and analyze their pathological characteristics and associated patient survival.

The study group comprised 47 patients (19 females and 28 males) with primary CRC who underwent colorectal resection at the H. Lee Moffitt Cancer Center between 1997 and 2002. These cases were selected based on the gross appearance of the tumors and after review of all of the hematoxylin and eosin-stained tumor sections in a series of 190 consecutive colorectal resections for CRCs. Application of strict morphological criteria classified 22 tumors as FCRCs. For comparison, 25 "polypoid" CRCs (PCRCs) were also identified. Cases of ulcerative fungating annular CRCs and CRCs with mixed gross appearance were excluded from this analysis. Clinicopathologic data, including patient survival, were compared for FCRCS and PCRCs. Statistical analyses were carried out using the chi(2) or Fisher's exact test and log-rank tests. Overall, 22 of 190 CRCs (11%) were found to meet the morphological criteria of FCRCs. Mean patient age was 70.6 years (range, 55 to 87) for FCRCs versus 68.5 years (range, 54 to 91) for PCRCs, and mean tumor size was 4.7 cm (range, 1.6 to 9) for FCRCs versus 4.4 cm (range, 0.5 to 10) for PCRCs. None of the 22 FCRCs and only 1 of 25 (4%) PCRCs were well differentiated; 17 of 22 (77%) FCRCs and 23 of 25 (92%) PCRCs were moderately differentiated; and 5 of 22 (22%) FCRCs and 1 of 25 (4%) PCRCs were poorly differentiated (P = 0.0087). FCRC cases were staged as 0 stage T1, 3 (14%) stage T2, and 19 (86%) stage T3; PCRC cases, as 4 (16%) stage T1, 14 (56%) stage T2, and 7 (28%) stage 3 (P = 0.000031). Similarly, angiolymphatic invasion was identified in 12 of 22 (54%) FCRCs versus 4 of 25 (16%) PCRCs (P = 0.0123). Although some differences between FCRCs and PCRCs were observed on resection in terms of nodal status (N), presence of metastases (M), and perineural invasion, these differences were not statistically significant. In comparison with PCRCs, FCRCs were associated with significantly shorter postresection patient survival at 1 to 5 years (P = 0.028).

We have demonstrated in this report that a proportion of primary CRCs resected at our institution were indeed "flat." Furthermore, these FCRCs exhibited higher histological grades, higher T stage, more frequent angiolymphatic invasion, and shorter patient survival compared with PCRCs. Based on these data, FCRC appears to be a worse subtype of colon cancer than PCRC. Further appraisal of FCRCs and additional studies to further elucidate the molecular mechanisms underlying their morphogenesis are warranted.
Sporadic Medullary Carcinoma of the Colon
A Clinicopathologic Comparison With Nonhereditary Poorly Differentiated Enteric-Type Adenocarcinoma and Neuroendocrine Colorectal Carcinoma

Mark R. Wick, MD, etal.
Am J Clin Pathol 2005;123:56-65 Abstract quote

We studied 68 sporadic colorectal carcinomas (CRCs) with medullary features (MCRCs) and compared them with 35 poorly differentiated purely "enteric" CRCs (ECRCs) and 15 purely neuroendocrine carcinomas (NECs) of grades II and III, all in patients lacking a family history of CRC.

Potential clinicopathologic differences between the study groups were assessed. MCRCs were significantly more common in the ascending colon than were ECRCs, but there was no significant dissimilarity to NECs. ECRCs occurred more often in the rectosigmoid than MCRCs or NECs. MCRCs arose in older patients, and a marked sex difference also was noted. Despite an infiltrative growth pattern, MCRC was less likely than ECRC to manifest with stage III or IV disease, but there was no stage-related difference from NECs.

Although the histologic images of MCRCs were evocative of neuroendocrine differentiation, chromogranin positivity and synaptophysin reactivity in that group did not differ meaningfully from that of ECRCs but was dissimilar to the 100% labeling of NECs. p53 immunolabeling was similar in the 3 tumor groups. Follow-up data in the study cases showed that 5-year mortality was 40% (27/68) for MCRC, 59% (19/32) for ECRC, and 93% (14/15) for NEC.

Medullary CRC seems to be a distinct clinicopathologic variant of CRC, which does not have a neuroendocrine lineage. The biologic behavior of MCRC was better than that of ECRC or NEC.

Hypermethylation of the hMLH1 promoter with absent hMLH1 expression in medullary-type poorly differentiated colorectal adenocarcinoma in the elderly.

Arai T, Esaki Y, Sawabe M, Honma N, Nakamura K, Takubo K.

Department of Pathology, Tokyo Metropolitan Geriatric Medical Center, Tokyo, Japan.
Mod Pathol. 2004 Feb;17(2):172-9 Abstract quote.  

To clarify the significance of hMLH1 promoter hypermethylation in the development of medullary-type poorly differentiated colorectal adenocarcinoma, we studied the status of promoter methylation and hMLH1 expression in 23 medullary-type and 12 pleomorphic-type carcinomas, as well as the pathology and microsatellite status. In medullary-type carcinomas, the percentages of cases with promoter methylation (83%) and an absence of hMLH1 expression (91%) were significantly higher than in pleomorphic-type carcinomas (14 and 17%), respectively. The rate of microsatellite instability in the medullary type was significantly higher than that of the pleomorphic type (87 vs 40%, P<0.01). Compared with pleomorphic-type carcinomas, medullary-type carcinomas were significantly associated with hMLH1 promoter methylation, absent expression of hMLH1 protein, microsatellite instability, as well as a proximal location, a Crohn's-like lymphoid reaction, a low incidence of lymph node metastasis, and a favorable outcome. Medullary-type carcinomas accumulated with advancing age, especially in the female. These results indicated that hMLH1 hypermethylation, concurrent with a lack of its protein expression, may play an important role in the development of medullary-type poorly differentiated colorectal adenocarcinomas in the elderly.
MUCINOUS (COLLOID) Abundant mucin lakes which dissect the connective tissue
Mucinous carcinoma of the colon: correlation of loss of mismatch repair enzymes with clinicopathologic features and survival.

Kakar S, Aksoy S, Burgart LJ, Smyrk TC.

1Department of Pathology, University of California San Francisco and Veteran Affairs Medical Center, San Francisco, CA, USA.
Mod Pathol. 2004 Jun;17(6):696-700. Abstract quote  

Colorectal carcinoma with microsatellite instability (MSI-H) has a characteristic clinicopathologic profile, typically forming right-sided, lymphocyte-rich tumors that are often mucinous. Mucinous histology in general has been linked to adverse prognosis in some studies, but not in others. MSI-H carcinoma, in contrast, has a better prognosis than microsatellite stable carcinoma in most studies.

We assessed the relationship between MSI status, clinicopathologic features and outcome for 248 consecutive patients with resected mucinous carcinoma. All cases were reviewed to confirm mucinous histology. Immunohistochemical stains for DNA mismatch repair enzymes hMLH1, hMSH2 and hMSH6 were performed on a representative block from each case. Tumors lacking expression of a mismatch repair enzyme were designated MSI-H; all others were classified as microsatellite stable. Age, sex, tumor size, site, grade, stage, growth pattern, Crohn's-like reaction, vascular invasion and number of tumor-infiltrating lymphocytes were evaluated without knowledge of MSI status or patient outcome. 72 (29.3%) mucinous carcinomas were MSI-H. Compared to microsatellite stable mucinous cancers, they were more likely to be right-sided (83.3 vs 48.6%, P<0.001), have a Crohn's -like reaction (65.7 vs 29.8%, P<0.001) and have many tumor infiltrating lymphocytes (72.2 vs 20.8%, P<0.001). MSI-H mucinous cancers presented more often as localized disease (66.7 vs 38.1%, P<0.001) and less often with lymph node (26.4 vs 44.9%) or distant (4.2 vs 16.5%) metastases. In univariate analysis, MSI had a favorable effect on age-adjusted survival (hazard ratio 0.597, P=0.02).

In multivariate analysis, age, grade, Crohn's-like reaction and stage were independent predictors of survival, but MSI status was not. In conclusion, MSI-H mucinous carcinomas are right-sided, low-stage tumors with Crohn's-like reaction and tumor-infiltrating lymphocytes. The outcome for MSI-H mucinous carcinoma is better than that of microsatellite-stable mucinous carcinoma, but MSI status is not an independent predictor of survival.
NEUROENDOCRINE Small cell carcinoma with positive staining for neuroendocrine markers

Increased endocrine cells in treated rectal adenocarcinomas: a possible reflection of endocrine differentiation in tumor cells induced by chemotherapy and radiotherapy.

Shia J, Tickoo SK, Guillem JG, Qin J, Nissan A, Hoos A, Stojadinovic A, Ruo L, Wong WD, Paty PB, Weiser MR, Minsky BD, Klimstra DS.

Departments of Pathology (J.S., S.K.T., D.S.K.), Surgery (J.G.G., A.N., A.H., A.S., L.R., W.D.W., P.B.P., M.R.W.), Radiation Oncology (B.D.M.).

Am J Surg Pathol 2002 Jul;26(7):863-72 Abstract quote

The presence of focal endocrine cells in colorectal adenocarcinoma is a relatively common phenomenon. However, endocrine differentiation in treated adenocarcinomas of the gastrointestinal tract has received little attention.

We noted striking numbers of cells with endocrine morphology and phenotype in the residual tumor of six randomly encountered cases of rectal adenocarcinoma that were subjected to neoadjuvant therapy. All six cases had a substantial treatment response (>/=50%).

To validate our initial observation and to explore its clinicopathologic significance, further morphologic and immunohistochemical studies were performed on 53 cases of rectal adenocarcinomas treated with preoperative radiation with (33 cases) or without (20 cases) chemotherapy. Pretreatment biopsies from 20 of the 53 cases and 79 resection specimens of rectal adenocarcinoma that received no neoadjuvant therapy were used as controls. Chromogranin positivity was identified in the posttreatment resection specimens in 36 of the 53 study cases (67.9%). Twenty of the 36 showed positive staining in >/=20% of the residual tumor cells. The chromogranin-positive cells in these cases often formed cords or nests. On hematoxylin and eosin sections these cells had markedly eosinophilic cytoplasm and round and uniform or sometimes pleomorphic nuclei with an often dense chromatin pattern. The proportion of chromogranin-positive cells was significantly associated with the extent of treatment response (p = 0.0005). Tumors treated with both chemotherapy and radiotherapy were more likely to have abundant chromogranin-positive cells compared with tumors treated with radiotherapy alone (p = 0.0004).

In contrast, only 30% of the pretreatment biopsies and 17.7% of the control resection specimens of untreated rectal carcinomas showed chromogranin-positive cells, predominantly arranged as scattered individual positive cells, constituting <10% of the tumor. No significant correlation was observed between pretreatment and posttreatment specimens with regard to chromogranin positivity (p = 1.0). Ten of 15 patients (66.7%) whose resection specimens showed positive chromogranin staining failed to demonstrate any chromogranin positivity in their pretreatment biopsy specimens. In addition, groups or nests of chromogranin-positive cells noted in posttreatment specimens showed a very low Ki67 labeling index (<5%) but showed a frequency of abnormal p53 protein expression comparable with that observed in tumor foci resembling conventional adenocarcinoma (66.7% vs 62.5%).

Our findings demonstrate that there is an increased frequency and density of cells with an endocrine phenotype in rectal adenocarcinomas that were subjected to neoadjuvant therapy and that the extent of endocrine cells appears proportional to the degree of treatment response. The possible mechanism for the increased endocrine cells in treated rectal adenocarcinomas may be related to induction of endocrine differentiation in tumor cells by cytotoxic insult.


Invasive papillary adenocarcinoma of the colon.

Palazzo JP, Edmonston TB, Chaille-Arnold LM, Burkholder S.

Departments of Pathology, Anatomy and Cell Biology and Microbiology and Immunology and the Genetics and Molecular Biology Program, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA.

Hum Pathol 2002 Mar;33(3):372-5 Abstract quote

Colonic adenocarcinomas are among the most common type of tumors.

In this report, we present the morphologic, immunohistochemical, and microsatellite findings of 2 cases with a distinct invasive papillary component. Both tumors arose from polyps in middle-aged patients, followed an aggressive course, and showed a superficial adenomatous component. The immunohistochemical stains showed that the tumor cells were negative for p27 and p53; both tumors were microsatellite stable, that is, with no microsatellite instability in the 6 markers studied, and there was no loss of the mismatch repair proteins hMSH2 or hMLH1.

These findings suggest that these tumors follow the tumor-suppressor pathway and represent an aggressive subtype of colonic adenocarcinoma.

Invasive colorectal micropapillary carcinoma: an aggressive variant of adenocarcinoma.

Kim MJ, Hong SM, Jang SJ, Yu E, Kim JS, Kim KR, Gong G, Ro JY.

Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 138-730, South Korea.

Hum Pathol. 2006 Jul;37(7):809-15. Abstract quote  

Micropapillary carcinoma (MC) has been well described in other organs, including breast, urinary bladder, lung, ovary, and salivary gland, but has not been described in the large intestine.

We compared the clinicopathologic and immunohistochemical findings of MC with those of conventional adenocarcinoma in the large intestine. Fifty-five cases of adenocarcinoma with an MC component were identified among 585 consecutive cases of colorectal cancer at the Asan Medical Center between January 2003 and June 2004 and were compared with 119 cases of conventional adenocarcinoma of colorectum without an MC component. Arrayed tissue blocks were constructed and immunostained for cytokeratin 7 and 20 and CDX2. We also compared the results of MLH-1, MSH-2, p53, and carcinoembryonic antigen immunostainings between the 2 groups.

The grade of both MC and conventional adenocarcinoma was mostly moderately differentiated. The proportion of MC ranged from 5% to 80%. The presence but not extent of MC in the primary tumors was associated with more frequent lymphovascular invasion and lymph node (LN) metastases, a greater mean number of positive LNs, and a higher tumor stage with more frequent distant metastases, compared with conventional adenocarcinoma (P < .05). Cytokeratin 7 staining was occasionally observed in both MC (9.1%, 5/55 cases) and conventional adenocarcinoma (13.4%, 16/119 cases). Although MLH-1 and CDX2 expression tended to be lower in conventional adenocarcinoma, none of the immunohistochemical results was significantly different between 2 groups. Recognition of MC component is important as MC appeared to be an aggressive variant of colonic adenocarcinoma and presented at a higher stage, with frequent lymphovascular invasion, LN metastasis, and distant metastasis, compared with conventional adenocarcinoma.

The proportion of MC component did not impact the prognosis, and the immunoprofiles of MC were not significantly different from those of conventional adenocarcinoma.

Signet ring cell carcinoma of the colorectum: correlations between microsatellite instability, clinicopathologic features and survival.

Kakar S, Smyrk TC.

1Department of Pathology, University of California San Francisco and Veteran Affairs Medical Center, San Francisco, CA, USA.
Mod Pathol. 2005;18:244-249 Abstract quote

Colorectal cancer with microsatellite instability has a characteristic clinicopathologic profile, featuring right-sided, lymphocyte-rich tumors with a better prognosis than microsatellite stable (MSS) carcinoma. Mucinous and signet ring cell carcinomas are both over-represented among microsatellite instability-high cancers. The clinicopathologic features of mucinous microsatellite instability-high cancer parallel those of the overall microsatellite instability-high set, but it is not known whether the same is true for signet ring cell carcinoma, particularly given the fact that signet ring histology is a well-documented adverse prognostic factor.

We recorded age, sex, tumor size, site, grade, stage, histologic pattern, growth pattern, Crohn-like reaction, vascular invasion and tumor-infiltrating lymphocytes in 72 resected signet ring cell carcinomas of the colorectum. Microsatellite instability was determined by a combination of polymerase chain reaction and immunohistochemical stains for hMLH1, hMSH2 and hMSH6. Tumors with instability at >30% of informative markers and/or loss of hMLH1 or hMSH2 expression were designated microsatellite instability-high; all others were classified as MSS. A total of 22 (31%) signet ring cell carcinomas were microsatellite instability-high. Compared to MSS signet ring cell carcinoma, they were more likely to be right-sided (81 vs 45%, P=0.005) and to affect older patients (68 vs 26%, P=0.0007) of female sex (59 vs 28%, P=0.03). Crohn-like reaction (45 vs 16%, P=0.02) and high tumor infiltrating lymphocyte counts (32 vs 8%, P=0.03) were more common in the microsatellite instability-high setting. There was no significant difference in 5-year survival in microsatellite instability-high vs MSS patients (41 vs 34%, P=0.3).

In conclusion, approximately one-third of signet ring carcinomas of the colorectum are microsatellite instability-high. Microsatellite instability-high signet ring carcinomas share clinicopathologic features with other microsatellite instability-high cancers: older age group, female preponderance, right-sided location, Crohn-like reaction and numerous tumor-infiltrating lymphocytes. Microsatellite instability status does not appear to be a significant predictor of survival in signet ring cell carcinoma of the colorectum.

Colon signet ring cell adenocarcinoma: immunohistochemical characterization and comparison with gastric and typical colon adenocarcinomas.

Goldstein NS, Long A, Kuan SF, Hart J.

Department of Pathology, William Beaumont Hospital, Royal Oak, Michigan 48073-6769, USA.

Appl Immunohistochem Molecul Morphol 2000 Sep;8(3):183-8 Abstract quote

Colon signet ring cell adenocarcinomas are uncommon, high-grade neoplasms. Given their rarity, the question of primary colon or metastatic gastric adenocarcinoma frequently arises when signet ring cell carcinoma is seen in a colonoscopic biopsy or in biopsies procured from other regions of the body. A second related question regarding colon and gastric signet ring cell carcinomas is their immunophenotypic similarities with the glandular form of adenocarcinoma in each site.

We studied the immunohistochemical phenotype of 14 colonic signet ring cell adenocarcinomas and compared them with immunophenotype of 27 gastric signet ring cell adenocarcinomas.

We also compared the immunophenotype of the 27 gastric signet ring cell with the immunophenotype of 19 gastric gland-forming adenocarcinomas, and the immunophenotype of the 14 colonic signet ring cell adenocarcinomas to the immunophenotype of 20 colonic gland-forming adenocarcinomas to identify staining differences in the neoplastic cells of the two architectures.

Antibodies studied were cytokeratins 7, 17, 19, and 20, CA 19-9, CA-125. estrogen receptor, and gross cystic disease fluid protein 15. Sixty-four percent of colon signet ring cell adenocarcinomas had either no staining or focal staining with cytokeratin 7 compared with diffuse staining in 63% of gastric signet ring cell adenocarcinomas (P = 0.016). Seventy-two percent of colon signet ring cell adenocarcinomas had diffuse staining with cytokeratin 20 compared with no or focal staining in 50% of gastric signet ring cell adenocarcinomas (P = 0.019). Fifty-seven percent of the colon signet ring cell adenocarcinomas had a cytokeratin 7 (-)/cytokeratin 20 (+) staining pattern compared with 11% of gastric signet ring cell adenocarcinomas (P = 0.004). Forty-four percent of gastric signet ring cell adenocarcinomas had a cytokeratin 7 (+)/cytokeratin 20 (-) pattern, compared with none of the colon signet ring cell adenocarcinomas (P = 0.004). The staining distribution of the antibody battery was similar in colon signet ring cell and colon glandular adenocarcinoma and gastric signet ring cell and gastric glandular adenocarcinomas.

When signet ring cell adenocarcinoma is encountered in a colon biopsy, a colon primary is supported if the neoplastic cells have a cytokeratin 7 (-)/cytokeratin 20 (+) staining pattern, and a gastric primary is supported if they have a cytokeratin 7 (+)/cytokeratin 20 (-) staining pattern. The signet ring morphology at each site had an identical immunophenotype as the cells forming their glandular counterpart.

Intestinal Low-grade Tubuloglandular Adenocarcinoma in Inflammatory Bowel Disease.

Levi GS
Harpaz N.

Mount Sinai School of Medicine, New York, NY.


Am J Surg Pathol. 2006 Aug;30(8):1022-29 Abstract quote

Chronic idiopathic inflammatory bowel disease (IBD) with extensive colonic involvement predisposes to the development of colorectal adenocarcinoma. Among the types of cancer occurring in this setting is an unusually well-differentiated low-grade tubuloglandular adenocarcinoma (LGTGA) that has not been studied systematically thus far.

A review of 149 IBD-associated cancer resections performed at our institution yielded 17 patients (11%) with 21 tumors classified as LGTGA based on the following histologic characteristics: very well-differentiated small to medium diameter glands with round or tubular profiles, low-grade cytologic characteristics and absence or paucity of desmoplastic reaction. Twelve patients had ulcerative colitis, 4 Crohn disease, and 1 indeterminate colitis. Their median age was 41.5 years (range, 28 to 58 y). Five patients had separate synchronous cancers of conventional types. LGTGAs ranged from 0.4 to 10 cm in size and varied in gross appearance. They included 5 flat lesions that were not identified visually but were detected either by palpation of the unfixed surgical specimen (1 case) or histologically in random sections (4 cases). The invasive glands usually bore a close histologic resemblance to overlying low-grade or indefinite dysplastic crypts. Twelve carcinomas (57%) with well-defined superficial regions of LGTGA progressed histologically to conventional adenocarcinoma in deeper regions.

These tumors were significantly more advanced than 9 carcinomas that maintained low-grade histology throughout. Follow-up of 13 patients (76%) for a mean 4.0 years (range, 0.75 to 9.0 y) disclosed 10 (77%) with favorable outcomes and 3 (23%) with adverse outcomes. Two adverse outcomes were attributable to synchronous advanced-stage conventional cancers and the third to progression from LGTGA to poorly differentiated adenocarcinoma. The mucosa overlying and surrounding LGTGA showed low-grade dysplasia (LGD) in 18 cases (86%), indefinite dysplasia with focal LGD in 1 case (5%), and LGD with focal high-grade dysplasia (HGD) in 2 cases (10%). Immunohistochemical studies disclosed expression of MUC2 in 72%, MUC6 in 0%, CK7 in 69%, and CK20 in 100%.

Coexpression of CK7 and CK20 was conserved in regions of conventional adenocarcinoma derived from LGTGA. Silencing of immunohistochemical expression of hMLH1 occurred in 6 of 11 tumors tested (55%), implicating defective DNA replication error repair in their pathogenesis. We conclude that LGTGA is a distinct clinicopathologic entity characterized by direct derivation from LGD mucosa of IBD, very well-differentiated morphology, frequent coexpression of CK7 and CK20, and frequent silencing of hMLH1. Histologic progression from LGTGA to conventional types of adenocarcinoma parallels clinical progression to more aggressive neoplasia.

The potential of LGD to give rise directly to LGTGA, and by way of LGTGA to more aggressive cancers, reinforces recommendations in favor of aggressive management of IBD patients diagnosed with LGD.
Villous adenocarcinoma of the colon and rectum: a clinicopathologic study of 36 cases.

Loy TS, Kaplan PA.

From the University of Missouri School of Medicine, Columbia, MO.

Am J Surg Pathol. 2004 Nov;28(11):1460-5. Abstract quote  

Some colorectal adenocarcinomas show villous architecture with morphologic similarities to tubulovillous or villous adenomas.

We reviewed 420 consecutive colorectal adenocarcinoma resection specimens and found that 95 tumors (23%) showed areas of villous architecture. Thirty-six tumors (8.6%) in 35 patients showed more than 50% villous architecture and were designated villous adenocarcinomas. Only 42% of the villous adenocarcinomas showed severe atypia and only 44% of the available pre-resection biopsies of these tumors were diagnosed as adenocarcinoma.

Epithelial islands in desmoplastic stroma (EIDS) may be helpful in the diagnosis of these tumors. EIDS were found in 97% of the resection specimens for villous adenocarcinomas and none of 62 resection specimens for tubulovillous or villous adenomas. The presence of EIDS showed a 67% sensitivity, 100% specificity, and 100% predictive value in the diagnosis of villous adenocarcinoma in a blinded review of villous tumors. On review of the pre-resection biopsies of villous adenocarcinoma without a final diagnosis of adenocarcinoma, 40% showed EIDS. Clinical follow-up of the 35 patients with villous adenocarcinoma showed that only one died of colorectal adenocarcinoma (median follow-up, 46 months). This sole patient dying of colorectal adenocarcinoma showed a synchronous advanced stage of nonvillous adenocarcinoma at the time of diagnosis.

Villous adenocarcinoma is a diagnostically challenging subset of colorectal adenocarcinoma, which appears to be associated with a favorable prognosis. Classifying these tumors as a special type of colorectal cancer may facilitate the development of diagnostic adjuncts and optimal treatment protocols.



Evaluation of the tissue microarray technique for immunohistochemical analysis in rectal cancer.

Fernebro E, Dictor M, Bendahl PO, Ferno M, Nilbert M.

Departments of Oncology (Drs Fernebro, Bendahl, Ferno, and Nilbert) and Pathology (Dr Dictor), University Hospital, Lund, Sweden.


Arch Pathol Lab Med 2002 Jun;126(6):702-5 Abstract quote

Background.-Immunohistochemical staining for tumor-associated proteins is widely used for the identification of novel prognostic markers. Recently, a tissue-conserving, high-throughput technique, tissue microarray, has been introduced. This technique uses 0.6-mm tissue core biopsy specimens, 500 to 1000 of which are brought into a new paraffin array block, which can be sectioned up to 100 times.

Methods.-We evaluated the tissue microarray technique for immunohistochemical analysis in 20 rectal cancers. Immunohistochemical staining was performed for the proliferation marker Ki-67 and the tumor suppressor protein p53 in whole tissue sections and in tissue core biopsy specimens.

Results.-The whole tissue sections were assessed by counting all cells in 10 high-power fields (x40), which resulted in a mean fraction of Ki-67-expressing tumor cells of 0.81 (range, 0.54-1.0). p53 expression assessed in whole tissue sections showed nuclear staining in 15 (75%) of 20 rectal carcinomas. For the tissue microarray technique, a median of 3 (range, 3-5) 0.6-mm tissue core biopsy specimens were studied from each of the 20 tumor specimens. The tissue microarray method gave a mean Ki-67 expression of 0.85 (range, 0.50-1.0) in tumor cell nuclei and showed p53 protein expression in the same 15 of 20 tumors as in the whole tissue sections.

Conclusion.-We conclude that the tissue microarray technique for immunohistochemical staining in rectal cancer yields staining of good quality and expression data for Ki-67 and p53 comparable to those obtained with whole tissue staining. The feasibility of tissue microarray thus enables time- and tissue-preserving studies of multiple markers in large tumor series.

Differential expression of alpha-methylacyl coenzyme A racemase in adenocarcinomas of the small and large intestines.

Chen ZM, Ritter JH, Wang HL.

Lauren V. Ackerman Laboratory of Surgical Pathology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110-1093, USA.

Am J Surg Pathol. 2005 Jul;29(7):890-6. Abstract quote  

Alpha-methylacyl coenzyme A racemase (AMACR), a novel immunomarker for prostatic adenocarcinoma, has recently been shown to be expressed in a number of malignancies including colorectal adenocarcinoma.

In the current study, 59 surgically resected primary small intestinal adenocarcinomas (34 ampullary and 25 non-ampullary) were immunohistochemically examined for AMACR expression and compared with 66 colorectal adenocarcinomas (including 24 secondary tumors involving the small intestine by direct extension or metastasis).

The results show that no AMACR immunoreactivity was detected in normal-appearing small and large intestinal mucosa. While 41 of 66 (62%) colorectal adenocarcinomas exhibited a variable degree of cytoplasmic staining, only 1 of 25 (4%) non-ampullary and 2 of 34 (6%) ampullary small intestinal adenocarcinomas showed positive AMACR immunoreactivity (P < 0.0001). Interestingly, AMACR appeared to be less frequently expressed in mucinous or poorly differentiated colorectal adenocarcinomas when compared with non-mucinous or better-differentiated counterparts, suggesting an association with microsatellite instability status.

These results extend our previous observations that small intestinal adenocarcinomas differ markedly from colorectal adenocarcinomas despite their morphologic similarity. The different AMACR expression patterns may not only provide an additional diagnostic tool in the distinction between adenocarcinomas of the small and large intestinal origins but may also shed light on further understanding of intestinal tumorigenesis.
Expression of the intestinal marker Cdx2 in secondary adenocarcinomas of the colorectum.

Groisman GM, Bernheim J, Halpern M, Brazowsky E, Meir A.

Department of Pathology, Hillel Yaffe Medical Center, Hadera, Israel.
Arch Pathol Lab Med. 2005 Jul;129(7):920-3. Abstract quote  

CONTEXT: Secondary adenocarcinomas of the large bowel can closely mimic primary tumors. The differentiation of secondary from primary adenocarcinomas of the colorectum, however, is important because their clinical management and prognosis are different. Immunostaining with the nuclear transcription factor Cdx2, expressed in normal intestinal epithelia and colorectal adenocarcinomas, could be of potential diagnostic use.

OBJECTIVE: To investigate the diagnostic value of Cdx2 immunoexpression in distinguishing primary from common forms of secondary colorectal adenocarcinomas.

DESIGN: Cdx2 immunoexpression was analyzed in 20 primary colorectal adenocarcinomas and in 34 secondary colorectal adenocarcinomas and their corresponding primary tumors. All secondary tumors were diagnosed through endoscopic biopsies and included 8 cases of ovarian (4 serous, 2 mucinous, and 2 endometrioid), 6 of mammary (4 lobular and 2 ductal), 4 of gastric (2 intestinal and 2 diffuse), 4 of pulmonary, 4 of pancreatic (ductal), 3 of prostatic, 3 of colorectal, and 2 of endometrial origin.

RESULTS: Cdx2 was expressed in normal colorectal epithelium, in primary colorectal adenocarcinomas (20/20 cases), in secondary adenocarcinomas of colorectal (3/3) and gastric (3/4) origin, and in metastatic ovarian mucinous adenocarcinomas (2/2). In contrast, no Cdx2 immunoreactivity was observed in secondary colorectal tumors of ovarian (serous and endometrioid), mammary, pancreatic, pulmonary, prostatic, and endometrial origin.

CONCLUSION: Cdx2 immunostaining may be useful in discriminating primary colorectal carcinomas from frequent types of secondary colorectal adenocarcinomas of nongastrointestinal origin. We suggest including Cdx2 in any antibody panel put together to distinguish between primary and secondary epithelial colorectal malignancies.

CDX2, a Highly Sensitive and Specific Marker of Adenocarcinomas of Intestinal Origin: An Immunohistochemical Survey of 476 Primary and Metastatic Carcinomas.

Werling RW, Yaziji H, Bacchi CE, Gown AM.

Am J Surg Pathol 2003 Mar;27(3):303-10 Abstract quote

CDX2 is a recently cloned homeobox gene that encodes an intestine-specific transcription factor, expressed in the nuclei of epithelial cells throughout the intestine, from duodenum to rectum. While expression of CDX2 protein in primary and metastatic colorectal carcinomas has been previously documented, neither the sensitivity nor the specificity of CDX2 expression, as determined by immunohistochemistry, for colorectal adenocarcinoma has been determined.

We performed an immunohistochemical survey of 476 tumors with a monoclonal antibody, CDX2-88, including 89 tumors from the colon and duodenum and 95 tumors from other gastrointestinal sites, including the esophagus, stomach, pancreatobiliary system, gastrointestinal carcinoids, and liver. CDX2 was expressed uniformly (that is, in 76-100% of tumor cells) in all but one of the evaluated colorectal and duodenal tumors. High-level expression of CDX2 was also found, however, in mucinous ovarian carcinomas and adenocarcinomas primary to the urinary bladder of which 64% and 100% were positive, respectively. Gastric, gastroesophageal, and pancreatic adenocarcinomas and cholangiocarcinomas all showed similar, heterogeneous patterns of CDX2 expression.

Most tumors in each group showed CDX2 expression by a minority of cells, whereas a substantial minority of cases in each group was completely negative and a smaller minority was uniformly positive. Gastrointestinal carcinoids gave similarly varied results, but the majority (58%) was negative. Hepatocellular carcinomas showed no expression of CDX2. Only very rare examples of carcinomas of the genitourinary and gynecologic tracts, breast, lung, and head and neck showed significant levels of CDX2 expression. In this study of primary and metastatic epithelial tumors, uniform CDX2 expression is demonstrated to be an exquisitely sensitive and highly, but incompletely, specific marker of intestinal adenocarcinomas.

Compared with villin, a previously described marker of GI adenocarcinomas, CDX2 demonstrated superior sensitivity and comparable specificity. CDX2 expression can be seen, however, in selected non-GI adenocarcinomas such as mucinous ovarian carcinomas and adenocarcinomas of the urinary bladder.

CDX-2 Homeobox Gene Expression Is a Reliable Marker of Colorectal Adenocarcinoma Metastases to the Lungs.

Barbareschi M, Murer B, Colby TV, Chilosi M, Macri E, Loda M, Doglioni C.

Am J Surg Pathol 2003 Feb;27(2):141-9 Abstract quote

Lung metastases from colorectal carcinomas (CRC) can be resected with improved survival. The distinction between primary lung adenocarcinomas and metastases from CRC may sometimes be difficult, especially on cytologic specimens or small bronchoscopic biopsies. Immunohistochemistry may be of help in this setting: available markers include TTF-1 and SP-A, which are markers of lung origin, whereas there are no good markers of intestinal origin, besides cytokeratin 7 and 20 coexpression pattern, which is not very specific. The nuclear CDX-2 transcription factor, which is the product of a homeobox gene necessary for intestinal organogenesis, is expressed in normal colonic epithelia and most colorectal adenocarcinomas, and could potentially be of diagnostic usefulness.

Our aim was to investigate CDX-2 immunohistochemical expression using a new monoclonal antibody and to verify if CDX-2 can be a reliable marker to identify the colorectal origin of lung metastases. CDX-2 expression was evaluated in formalin-fixed, paraffin-embedded samples of normal adult human tissues (50 samples) and in 299 surgically resected carcinomas of different origins, including 125 non-lung adenocarcinomas, 117 primary lung tumors, 5 mesotheliomas, and 52 adenocarcinomas metastatic to the lung. CDX-2 was also evaluated on a series of 20 bioptic and 10 cytologic specimens (5 cases of colorectal metastases to the lung, 5 cases of metastases from other organs, and 10 primary lung adenocarcinomas). In normal tissues CDX-2 immunoreactivity was observed only in ileal and colorectal epithelia. CDX-2 was expressed in almost all primary and metastatic CRC (88 of 90) and was never observed in primary lung tumors. CDX-2 was also expressed in a limited group of adenocarcinomas of other sites (gastric, biliopancreatic, and mucinous ovarian adenocarcinomas).

CDX-2 could be easily detected in all bioptic and cytologic samples of CRC metastases. CDX-2 is a reliable, specific, and sensitive immunohistochemical marker of normal and neoplastic intestinal epithelium. CDX-2 can be easily applied to routine histologic and cytologic material and is therefore a useful marker in the differential diagnosis of primary versus metastatic adenocarcinomas in the lung, and among metastases from an unknown primary, supports intestinal origin.

CK20 and CK7 protein expression in colorectal cancer: Demonstration of the utility of a population-based tissue microarray.

Hernandez BY, Frierson HF, Moskaluk CA, Li YJ, Clegg L, Cote TR, McCusker ME, Hankey BF, Edwards BK, Goodman MT.
Hum Pathol. 2005 Mar;36(3):275-81. Abstract quote  

Summary The ability to use archival tissue to test externally valid hypotheses of carcinogenesis is dependent on the availability of population-based samples of cancer tissue. Tissue microarrays (TMAs) provide an efficient format for developing population-based samples of tissue. A TMA was constructed consisting of archival tissue from patients diagnosed with invasive colorectal cancer in the state of Hawaii in 1995. The population representativeness of the TMA was evaluated by comparing patient and clinical characteristics of TMA cases to that of all cases of colorectal carcinoma diagnosed statewide in 1995.

Cytokeratin 20 (CK20) and cytokeratin 7 (CK7) immunohistochemistry was used to validate the utility of the TMA, and the expression of these proteins was correlated with patient and tumor characteristics. The TMA comprised tissue specimens from 286 patients representing 47% of all invasive cases diagnosed statewide in 1995. TMA cases were comparable to all invasive colorectal cases statewide with respect to age, sex, race/ethnicity, anatomic site, and survival. There were some differences between TMA cases and all cases with respect to tumor stage, histological classification, and treatment. There were significant differences in the relative expression of CK20 and CK7 proteins between malignant and normal tissues and by tumor stage.

Advanced cancers were more likely to have CK20+/cytokeratin 7+ (CK7+) profiles than early-stage cancers, which were predominantly CK20+/cytokeratin 7- (CK7-). CK7+ expression was not correlated with anatomic location of carcinomas.

This well-characterized TMA offers a powerful tool for testing hypotheses regarding colorectal carcinogenesis, including the identification of potential markers of neoplastic development and progression.
Reduced expression of cytokeratin 20 in colorectal carcinomas with high levels of microsatellite instability.

McGregor DK, Wu TT, Rashid A, Luthra R, Hamilton SR.

Departments of Pathology and Hematopathology, Division of Pathology and Laboratory Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.
Am J Surg Pathol. 2004 Jun;28(6):712-8. Abstract quote  

High levels of microsatellite instability (MSI-H) result from abnormal nucleotide mismatch repair in a subset of sporadic colorectal carcinomas (CRC) and in most CRC of hereditary non-polyposis colorectal cancer syndrome. CRC with MSI-H have distinctive clinical-pathologic features, but the immunophenotype has not been studied extensively.

We evaluated immunohistochemical expression of cytokeratin 7 (CK7), cytokeratin 20 (CK20), and pancytokeratin (panCK) in 44 CRC from 22 paired MSI-H and microsatellite-stable (MSS) cases matched for clinical-pathologic characteristics.

The mean percentage of CK20+ tumor cells was 84 +/- 6% in MSS CRC but only 37 +/- 8% in MSI-H CRC (P = 0.0007). Thirty-two percent (7/22, 95% confidence interval 14-55%) of MSI-H CRC were CK20-, as contrasted with 9% (2/22, 95% CI 1-29%, P = 0.13) of MSS CRC. CK20 expression was inversely correlated with levels of MSI (rs = -0.45, P = 0.006). CK7+ was infrequent (16%, 7/44, 95% CI 7-30%) and panCK+ was universal, with no significant differences between MSI-H and MSS CRC. Our study shows that decreased or even absent CK20 expression is a phenotypic characteristic of MSI-H CRC and that MSI-H explains much of the subset of CRC that lack CK20 expression.

Our results also indicate that regulation of CK20 gene expression involves molecular pathways that are altered by MSI-H.

Cytokeratin Subset Immunostaining in Rectal Adenocarcinoma and Normal Anal Glands

Preetha Ramalingam, MD, William R. Hart, MD, and John R. Goldblum, MD

From the Division of Pathology and Laboratory Medicine, Department of Anatomic Pathology, Cleveland Clinic Foundation, Cleveland, Ohio.

Arch Pathol Lab Med 2001;125:1074–1077. Abstract quote

Context. —A large percentage of cases of perianal Paget disease are associated with an internal cancer, most commonly rectal adenocarcinoma. Immunostains for cytokeratin 7, cytokeratin 20, and gross cystic disease fluid protein 15 are useful in identifying cases associated with rectal adenocarcinoma. The Paget cells and rectal adenocarcinoma cells of these lesions typically have a cytokeratin 7+/cytokeratin 20+/gross cystic disease fluid protein 15 immunophenotype. It is not known whether rectal adenocarcinoma unassociated with perianal Paget disease has the same cytokeratin profile as rectal adenocarcinoma associated with perianal Paget disease.

Objective. —To evaluate the immunohistochemical cytokeratin 7 and 20 profile of resected rectal adenocarcinoma unassociated with perianal Paget disease as well as that of normal anal glands from hemorrhoidectomy specimens.

Design. —We performed immunohistochemistry for cytokeratins 7 and 20 on tissues from 30 cases of rectal adenocarcinoma unassociated with perianal Paget disease and 12 hemorrhoidectomy specimens from 12 cases with normal anal glands. We defined positive staining as any immunoreactivity within the neoplastic cells.

Results.—Twenty-six of 30 cases of rectal adenocarcinoma (87%) had a cytokeratin 7 /cytokeratin 20+ immunophenotype, similar to the immunophenotype of cases of nonrectal large intestine adenocarcinoma. In 4 cases (13%), neoplastic cells coexpressed cytokeratins 7 and 20. Anal glands stained strongly for cytokeratin 7 but were negative for cytokeratin 20 in all cases, and the anal transitional zone mucosa had a similar immunophenotype.

Conclusions. —Rectal adenocarcinoma unassociated with perianal Paget disease has a cytokeratin profile similar to that of nonrectal large intestine adenocarcinoma. These data suggest that rectal adenocarcinoma unassociated with perianal Paget disease has a different cytokeratin profile than rectal adenocarcinoma associated with perianal Paget disease.

Expression of cytokeratins 7 and 20 in primary carcinomas of the stomach and colorectum and their value in the differential diagnosis of metastatic carcinomas to the ovary.

Park SY, Kim HS, Hong EK, Kim WH.

Center for Colorectal Cancer, Center for Gastric Cancer, and Department of Pathology, National Cancer Center, Goyang, Gyeonggi, Korea and the Department of Pathology, Seoul National University College of Medicine, Seoul, Korea.


Hum Pathol 2002 Nov;33(11):1078-85 Abstract quote

The expressions of cytokeratin (CK) 7 and 20 have been studied in various primary and metastatic carcinomas, and their determination may help distinguish the site of origin of metastatic carcinomas. However, little is known about the factors that determine variations in their expression patterns in primary gastric and colorectal carcinomas.

We investigated the expressions of CK7 and CK20 in 289 cases of gastric carcinoma and 225 cases of colorectal carcinoma using a tissue microarray. To evaluate CK7 and CK20 expression patterns of ovarian metastases from gastric or colorectal carcinomas, 54 cases of metastatic carcinomas to the ovary were examined. It was found that 71% (207 of 289) of the gastric carcinomas stained positively for CK7, whereas only 9% (21 of 225) of the colorectal carcinomas proved to be CK7 positive, and that 41% (117 of 289) of the gastric carcinomas and 73% (165 of 225) of the colorectal carcinomas were CK20 positive.

The proportion of CK7+/CK20- was highest in the gastric carcinomas at 46% (132 of 289), and was independent of the histologic classification of Lauren (46% of the intestinal type, 45% of the diffuse type). The CK7 and CK20 expression patterns were different in colorectal carcinomas according to histologic grade and location of the tumor. CK7-/CK20+ had the greatest proportion (68%) in colorectal carcinomas, and this was dependent on the tumor's histologic grade (75% of low-grade versus 52% of high-grade) and location (46% of right-sided versus 76% of left-sided). Moreover, 42% (18 of 43) of gastric carcinomas metastatic to the ovary were CK7+/CK20-, whereas 19% (8 of 43) were CK7-/CK20+. All colorectal cancers metastatic to the ovary were CK7-/CK20+, except 1 case that was CK7-/CK20-.

In conclusion, the CK7 and CK20 expression patterns in primary gastric carcinomas vary considerably, and those in colorectal carcinomas are associated with histologic grade and tumor location. The CK7-/CK20+ expression pattern is specific for metastatic colorectal carcinomas to the ovary, but has low predictability for colorectal origin in metastatic ovarian carcinoma.


Estrogen receptor is expressed in human colorectal adenocarcinoma

Deborah Witte, MD
Minni Chirala, BS
Anas Younes, MD
Yang Li, MS
Mamoun Younes, MD

Hum Pathol 2001;32:940-944 Abstract quote

Estrogen receptor (ER-) has recently been detected in a human colon cancer cell line. The aim of this work was to determine whether ER- is expressed in human colorectal carcinoma (CRC) tissue and the extent of this expression.

ER- expression in CRC was investigated by immunohistochemical staining of sections of formalin-fixed, paraffin-embedded tissue from 55 CRC. The percent of positive cells was recorded. ER- immunoreactivity was always present in normal epithelium and adenomas in the same sections of some CRC and was always nuclear. In CRC, nuclear ER- immunoreactivity was detected in >10% of the cancer cells in 67% of the cases and was almost always associated with cytoplasmic immunoreactivity. There were no statistically significant differences between the ER-–positive and –negative groups in regard to depth of invasion, nodal metastases, or survival, regardless of the cut-off value used.

We conclude that (1) a significant number of CRCs are positive for ER-. (2) estrogen may play an important role in the proliferation of normal colonic epithelium, and (3) there is differential localization of ER- immunoreactivity between normal colon, adenomas, and CRCs. Whether different ER- isoforms are differentially expressed in CRCs, and whether human CRCs respond to treatment with antiestrogens, is the subject of studies currently in progress.

Defective Mismatch-Repair Colorectal Cancer
Clinicopathologic Characteristics and Usefulness of Immunohistochemical Analysis for Diagnosis

Rodrigo Jover, MD, etal.
Am J Clin Pathol 2004;122:389-394 Abstract quote

The purpose of our study was to determine the usefulness of immunohistochemical analysis for the diagnosis of mismatch-repair (MMR) gene defective colorectal tumors and to describe their prevalence and clinicopathologic characteristics.

We studied 172 cases. DNA was extracted from formalin-fixed, paraffin-embedded surgical samples, and microsatellite analysis was performed by polymerase chain reaction with BAT-26. The results were correlated with immunohisto-chemical analysis for hMLH1 and hMSH2. Microsatellite instability (MSI) was detected in 13 (7.6%) tumors, and all showed loss of protein expression of hMLH1 (11/13) or hMSH2 (2/13) (P < .000). Patients with MMR-defective tumors more frequently had poorly differentiated tumors (5/13 [38%] vs 18/159 [11.3%]; P = .02) located in the ascending colon (8/13 [62%] vs 30/159 [18.9%]; P < .0001) and a personal history of other neoplasms (4/13 [31%] vs 18/159 [11.3%]; P = .05). There were no differences in age, family history of cancer, or TNM stage.

Immunohistochemical analysis seems to be a reliable method to detect most colorectal cancers with defective MMR genes.


Endometrioid Adenocarcinoma Arising from Colonic Endometriosis Mimicking Primary Colonic Carcinoma

Karl T. K. Chen, M.D.

From the Department of Pathology, Saint Agnes Medical Center, Fresno, California.

Int J Gynecol Pathol 2002 Jul;21(3):285-8 Abstract quote

The clinicopathologic features of a case of endometrioid adenocarcinoma arising from colonic endometriosis that clinically and histologically mimicked a primary colonic carcinoma are reported.

The differential diagnostic features of the tumor leading to the correct diagnosis included associated endometriosis, a minor mucosal component, focal squamous differentiation, absence of dirty necrosis, low nuclear grade, absence of a colonic adenoma, and a CK7+/CK20–/CEA– immunophenotype.

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Weedon D. Weedon's Skin Pathology Second Edition. Churchill Livingstone. 2002
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-Most commonly used clinicopathologic staging system for colon cancer.

Tumor Stage Histology
A Limited to mucosa
B1 Extending into the muscularis propria but not penetrating through it; uninvolved lymph nodes
B2 Penetrating through the muscularis propria; uninvolved lymph nodes
C1 Extending into the muscularis propria but not penetrating through it; involved nodes
C2 Penetrating through the muscularis propria; involved nodes
D Distant metastatic spread


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