Determining whether a tumor exhibits microsatellite instability (MSI) is useful in identifying patients with hereditary non-polyposis colorectal cancer and sporadic gastrointestinal cancers with defective DNA mismatch repair (MMR). The assessment of MSI status aids in establishing a clinical prognosis and may be predictive of tumor response to chemotherapy. A reference panel of five markers was suggested for MSI analysis by a National Cancer Institute (NCI) workshop in 1997 that has helped to standardize testing. But this panel of markers has limitations resulting from the inclusion of dinucleotide markers, which are less sensitive and specific for detection of tumors with MMR deficiencies compared to other types of markers that are currently available. This study demonstrates that mononucleotides are the most sensitive and specific markers for detection of tumors with defects in MMR and identifies an optimal panel of markers for detection of MSI-H tumors. A set of 266 mono-, di-, tetra- and penta-nucleotide repeat microsatellite markers were used to screen for MSI in colorectal tumors. The best markers for detection of MSI-H tumors were selected for a MSI Multiplex System, which included five mononucleotide markers: BAT-25, BAT-26, NR-21, NR-24 and MONO-27. In addition, two pentanucleotide markers were added to identify sample mix-ups and/or contamination. We classified 153 colorectal tumors using the new MSI Multiplex System and compared the results to those obtained with a panel of 10 microsatellite markers combined with immunohistochemical (IHC) analysis. We observed 99&#37; concordance between the two methods with nearly 100&#37; accuracy in detection of MSI-H tumors. Approximately 5&#37; of the MSI-H tumors had normal levels of four MMR proteins and as a result would have been misclassified based solely on IHC analysis, emphasizing the importance of performing MSI testing. The new MSI Multiplex System offers several distinct advantages over other methods of MSI testing in that it is both extremely sensitive and specific and amenable to high-throughput analysis. The MSI Multiplex System meets the new recommendations proposed at the recent 2002 NCI workshop on HNPCC and MSI testing and overcomes problems inherent to the original five-marker panel. The use of a single multiplex fluorescent MSI assay reduces the time and costs involved in MSI testing with increased reliability and accuracy and thus should facilitate widespread screening for microsatellite instability in tumors of patients with gastrointestinal cancers.

Jeffery W. Bacher

Laura A. Flanagan

Regenia L. Smalley

Nadine A. Nassif

Lawrence J. Burgart

Richard B. Halberg

Wael M. Abdel Megid

Stephen N. Thibodeau

Development of a Fluorescent Multiplex Assay for Detection of MSI-High Tumors

Annelie Liljegren

Louise Olsson

Annika Lindblom

MSI Test to Distinguish between HNPCC and Other Predisposing Syndromes &#x2013; of Value in Tailored Surveillance

The aim of this paper is to indicate how the pathologist may suspect a diagnosis of hereditary non-polyposis colorectal cancer (HNPCC) on the basis of histological criteria and patient age alone. A single morphological feature, namely the presence of intra-epithelial lymphocytes (tumor infiltrating lymphocytes), identifies the majority of colorectal cancers (CRC) with the DNA microsatellite instability-high phenotype. A number of pathological criteria can help to distinguish HNPCC from sporadic MSI-H CRC, though age below 60 years is an important pointer towards HNPCC. Immunohistochemistry to demonstrate loss of expression of DNA mismatch repair genes serves as a highly reliable test of mismatch repair deficiency if antibodies to hMLH1, hMSH2, hMSH6 and hPMS2 are employed.

Jeremy R. Jass

Role of the Pathologist in the Diagnosis of Hereditary Non-Polyposis Colorectal Cancer

Microsatellite instability (MSI) is a well-recognized phenomenon that is classically a feature of tumors in the hereditary non-polyposis colorectal syndrome. Ten to 15&#37; of sporadic colorectal cancers, however, will have MSI. Microsatellite unstable tumors can be divided into two distinct MSI phenotypes: MSI-high (MSI-H) and MSI-low (MSI-L). MSI sporadic colorectal cancers with a high level of MSI (MSI-H) form a well defined group with distinct clinicopathologic features characterized by an overall better long-term prognosis. These sporadic MSI-H colorectal tumors most often arise from the epigenetic silencing of the mismatch repair gene MLH1. In contrast, MSI-L colorectal tumors have not been shown to differ in their clinicopathologic features or in most molecular features from microsatellite stable (MSS) tumors. Unlike MSI-H tumors, MSI-L tumors appear to arise through the chromosomal instability carcinogenesis pathway, similar to MSS tumors. Some groups have reported more frequent mutations in K-ras and in the methylation of methylguanine transferase in MSI-L tumors, but others have questioned these findings. Therefore, although the use of the MSI-L category is widespread, there continues to be some debate as to whether a discrete MSI-L group truly exists. Rather, it has been suggested that MSI-L tumors differ quantitatively from MSS tumors but do not differ qualitatively. Future studies will need to evaluate the specific mutations in non-MSI-H tumors in an attempt to sub-classify MSI-L tumors with regard to MSS tumors so that subtle differences between these two sub-groups can be identified.

Timothy M. Pawlik

Chandrajit P. Raut

Miguel A. Rodriguez-Bigas

Colorectal Carcinogenesis: MSI-H Versus MSI-L

Hereditary nonpolyposis colorectal cancer (HNPCC, Lynch syndrome) is a dominantly inherited syndrome characterized by the development of colorectal cancer, endometrial cancer and other cancers and the presence of microsatellite instability (MSI) in tumors. The Bethesda guidelines have been proposed for the identification of families suspected of HNPCC that require further molecular analysis. We have evaluated the yield of MSI-analysis in a large series of Dutch families suspected of HNPCC. We also analysed whether the loss of mismatch repair (MMR) protein detected by immunohistochemistry (IHC) of colorectal cancer (CRC) and endometrial cancer correlated with the presence of MSI and/or a MMR gene mutation. The results showed that the Bethesda criteria with a few modifications are appropriate to identify families eligible for genetic testing. In addition, we found that MSI and IHC-analysis of CRC using antibodies against MLH1, MSH2, MSH6 and PMS2 proteins are equally effective for identifying carriers of the known MMR gene defects. However, as long as the role of other putative MMR genes in hereditary CRC has not been elucidated, IHC-analysis cannot completely replace MSI. For this reason, we prefer MSI-analysis as first step in families suspected of HNPCC. On the other hand, in families fulfilling the revised Amsterdam criteria in which the probability of detecting a mutation is relatively high, we would recommend IHC as first diagnostic step because the result might predict the specific underlying MMR gene mutation. MSI or IHC-analysis of endometrial cancer alone was found to be less sensitive compared with these tests performed in colorectal cancer. Therefore, probably the best approach in the analysis of this cancer is to perform both techniques. The identification of HNPCC is important as it makes it possible to target effective preventative measures. Our studies showed that MSI and IHC analysis of colorectal and endometrial cancer, are reliable cost-effective tools that can be used to identify patients with HNPCC.

H. F. A. Vasen

Y. Hendriks

A. E. de Jong

M. van Puijenbroek

C. Tops

A. H. J. T. Br&#xf6;cker-Vriends

J. Th. Wijnen

H. Morreau

Identification of HNPCC by Molecular Analysis of Colorectal and Endometrial Tumors

Genomic instability at simple repeated sequences, termed microsatellite instability (MSI), plays an important role in the analysis of sporadic and hereditary colon cancers. In hereditary non-polyposis colorectal cancer syndrome (HNPCC) more than 90&#37; of cases show MSI, whereas only 10&#x2013;15&#37; of sporadic colorectal cancers do so. Thus, microsatellite analysis is commonly used as the first diagnostic screening test for HNPCC. In 1997, an international collaborative workshop sponsored by the National Cancer Institute (NCI) proposed a set of guidelines for MSI-testing to improve reliability and reproducibility of the analysis as well to allow comparisons between different studies and different laboratories. In this review we assess the value of current protocols forMSI-testing and discuss some diagnostic pitfalls. Our findings support continued use of the MSI marker panel recommended in 1997. Additionally, MSI-testing should be improved by use of microdissection, which helps to identify additional patients with MSI due to enrichment of tumor cells and therefore increased sensitivity. In our view, immunohistochemical staining for mismatch repair protein expression is not a substitute for MSI-analysis but complements MSI screening and helps direct further testing. In summary, MSI-analysis is a highly sensitive and reliable screening method for HNPCC, that requires a well-equipped laboratory as well as an experienced pathologist. Integration of family history and histo-pathological features is also critical.

Annegret M&#252;ller

Tina Bocker Edmonston

Wolfgang Dietmaier

Reinhard B&#252;ttner

Richard Fishel

Josef R&#252;schoff

MSI-Testing in Hereditary Non-Polyposis Colorectal Carcinoma (HNPCC)

In 1994, the International Collaborative Group on Hereditary Nonpolyposis Colorectal Cancer (ICG-HNPCC) established an international database of mutations identified in families with Lynch (HNPCC) syndrome. The data are publicly available at http://www.nfdht.nl. The information stored in the database was systematically analyzed in 1997, and at that time, 126 different predisposing mutations were reported affecting the DNA mismatch repair genes MSH2 and MLH1 and occurring in 202 families. In 2003, the ICG-HNPCC and the Leeds Castle Polyposis Group (LCPG) merged into a new group, INSiGHT (International Society for Gastrointestinal Hereditary Tumors). The present update of the database of DNA mismatch repair gene mutations of INSiGHT includes 448 mutations that primarily involve MLH1 (50&#37;), MSH2 (39&#37;), and MSH6 (7&#37;) and occur in 748 families from different parts of the world.

P&#xe4;ivi Peltom&#xe4;ki

Hans Vasen

Mutations Associated with HNPCC Predisposition &#x2014; Update of ICG-HNPCC/INSiGHT Mutation Database

Extent neuroendocrine differentiation can be encountered in many human neoplasm derived from different organs and systems using immunohistochemistry and ultrastructural techniques. The tumor cells' behaviors resemble those of neurons and neuroendocrine cells. The presence of neuroendocrine differentiation reputedly appears to be associated with a poorer prognosis than the adenocarcinoma counterparts in sporadic human neoplasm. In this review the neuroendocrine carcinoma and the adenocarcinoma with neuroendocrine differentiation of colon and rectum both in sporadic colorectal carcinoma and the hereditary nonpolyposis colorectal cancer, the relationship of neuroendocrine differentiation and some possible molecular pathways in tumorogenesis of colorectal cancer will be discussed. Possible treatment strategy will also be addressed.

M. H. Sun

Neuroendocrine Differentiation in Sporadic CRC and Hereditary Nonpolyosis Colorectal Cancer

Microsatellite instability (MSI) analysis is becoming more and more important to detect sporadic primary tumors of the MSI phenotype as well as in helping to determine Hereditary Non-Polyposis Colorectal Cancer (HNPCC) cases. After some years of conflicting data due to the absence of consensus markers for the MSI phenotype, a meeting held in Bethesda to clarify the situation proposed a set of 5 microsatellites (2 mononucleotide repeats and 3 dinucleotide repeats) to determine MSI tumors. A second Bethesda consensus meeting was held at the end of 2002. It was discussed here that the 1998 microsatellite panel could underestimate high-level MSI tumors and overestimate low-level MSI tumors. Amongst the suggested changes was the exclusive use of mononucleotide repeats in place of dinucleotide repeats. We have already proposed a pentaplex MSI screening test comprising 5 quasimonomorphic mononucleotide repeats. This article compares the advantages of mono or dinucleotide repeats in determining microsatellite instability.

Olivier Buhard

Nirosha Suraweera

Aude Lectard

Alex Duval

Richard Hamelin

Quasimonomorphic Mononucleotide Repeats for High-Level Microsatellite Instability Analysis

Asad Umar

Lynch Syndrome (HNPCC) and Microsatellite Instability

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Disease Markers publishes papers related to the identification of disease markers, the elucidation of their role and mechanism, as well as their application in the prognosis, diagnosis and treatment of diseases.

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Chief Editor Paola Gazzaniga is an Associate Professor in the Department of Molecular Medicine at Sapienza University of Rome, Italy. Her core research focuses on liquid biopsies in patients with solid tumors.

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Disease Markers publishes papers related to the identification of disease markers, the elucidation of their role and mechanism, as well as their application in the prognosis, diagnosis and treatment of diseases.

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Disease Markers | Hindawi

Disease Markers

This Issue is now open for submissions.
Papers are published upon acceptance, regardless of the Special Issue publication date.

Disease Markers

Lynch Syndrome (HNPCC) and Microsatellite Instability

Lynch Syndrome (HNPCC) and Microsatellite Instability

Articles

Development of a Fluorescent Multiplex Assay for Detection of MSI-High Tumors

MSI Test to Distinguish between HNPCC and Other Predisposing Syndromes – of Value in Tailored Surveillance

Role of the Pathologist in the Diagnosis of Hereditary Non-Polyposis Colorectal Cancer

Colorectal Carcinogenesis: MSI-H Versus MSI-L

Identification of HNPCC by Molecular Analysis of Colorectal and Endometrial Tumors

MSI-Testing in Hereditary Non-Polyposis Colorectal Carcinoma (HNPCC)

Mutations Associated with HNPCC Predisposition — Update of ICG-HNPCC/INSiGHT Mutation Database

Neuroendocrine Differentiation in Sporadic CRC and Hereditary Nonpolyosis Colorectal Cancer

Quasimonomorphic Mononucleotide Repeats for High-Level Microsatellite Instability Analysis

Lynch Syndrome (HNPCC) and Microsatellite Instability