Mutations of hMLH1 and hMSH2 in Patients With Suspected Hereditary Nonpolyposis Colorectal Cancer: Correlation With Microsatellite Instability and Abnormalities of Mismatch Repair Protein Expression

2002 ◽  
Vol 20 (5) ◽  
pp. 1203-1208 ◽  
Author(s):  
Mario Scartozzi ◽  
Francesca Bianchi ◽  
Saverio Rosati ◽  
Eva Galizia ◽  
Annalisa Antolini ◽  
...  
Keyword(s):  
Gene Expression ◽  
Colorectal Cancer ◽  
Protein Expression ◽  
Microsatellite Instability ◽  
Mismatch Repair ◽  
Hereditary Nonpolyposis Colorectal Cancer ◽  
Germ Line ◽  
Missense Mutations ◽  
Hereditary Nonpolyposis ◽  
Germ Line Mutations

PURPOSE: The relationship between germ-line mutations of hMSH2 and hMLH1, microsatellite instability (MSI), and loss of DNA mismatch repair (MMR) gene expression were studied to formulate an effective selection protocol for patients with suspected hereditary nonpolyposis colorectal cancer who should be offered genetic testing. PATIENTS AND METHODS: Patients eligible for germ-line analysis of hMLH1 and hMSH2 were selected. Tumor specimens were obtained to assess MSI and loss of MMR gene expression. RESULTS: Among 37 patients who participated in the study, two hMSH2 and two hMLH1 missense mutations (11%) were detected, none of which was found in a panel of 60 healthy volunteers. High MSI was found in five tumors (19%) and low MSI in 10 tumors (39%); 12 tumors (46%) were microsatellite stable. Four tumors demonstrated loss of hMLH1, and three tumors demonstrated loss of hMSH2 protein expression. CONCLUSION: No relationship was found between MMR gene mutations and MSI; low or no MSI was found in the four patients with germ-line mutations, and none of the five patients with high MSI demonstrated abnormalities of MMR genes. On the contrary, loss of hMLH1 or hMSH2 expression was found in the tumors from three of the four patients demonstrating germ-line mutations. These data suggest that germ-line mutations of the MMR gene can occur in people with MSI-negative tumors. Sensitive clinical criteria and the study of MMR gene expression may be useful to identify this subset of patients.

Clinicopathologic and Pedigree Differences in Amsterdam I–Positive Hereditary Nonpolyposis Colorectal Cancer Families According to Tumor Microsatellite Instability Status

2007 ◽  
Vol 25 (7) ◽  
pp. 781-786 ◽  
Author(s):  
Laura Valle ◽  
Jose Perea ◽  
Pablo Carbonell ◽  
Victoria Fernandez ◽  
Ana M. Dotor ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Protein Expression ◽  
Microsatellite Instability ◽  
Mismatch Repair ◽  
Hereditary Nonpolyposis Colorectal Cancer ◽  
Repair System ◽  
Primary Tumors ◽  
Multiple Primary Tumors ◽  
Hereditary Nonpolyposis ◽  
Multiple Primary

Purpose To establish the clinicopathologic and familial differences within Amsterdam I–positive families, showing either tumor microsatellite instability (MSI) or microsatellite stability (MSS) in order to confirm or deny the existence of hereditary nonpolyposis colorectal cancer (HNPCC) without defects in the mismatch repair system. Patients and Methods Sixty-four Amsterdam I–positive families were included in the study for which full, three-generation, family medical histories and colorectal paraffin-embedded tumors were obtained. Both personal and clinicopathologic information of patients were collected. In all cases, both the MSI status and the mismatch repair (MMR) protein expression were analyzed. MMR genetic testing was performed on the MSI families. Results Of the Amsterdam I–positive families, 59.4% were tumor MSI, and 40.6% were tumor MSS. When comparing both groups, the statistical differences were observed in the age of onset (MSI, 41 years; MSS, 53 years); in the colorectal tumor location, more frequently proximal in MSI cases; in fewer mucinous tumors in MSS; and loss of MMR protein expression in the MSI tumors. Regarding the individual and familial cancer history, we observed a predominance of individuals with multiple primary tumors in MSI pedigrees, as well as differences in the type of tumors developed within the family. Conclusion Our findings support the suspicion of another hereditary colorectal syndrome different from HNPCC and characterized by MSS, the normal MMR immunohistochemical expression, the presence of only colorectal tumors, and the absence of individuals with multiple primary tumors. All these circumstances suggest the existence of a non-MMR gene being responsible for this new syndrome.

Microsatellite Instability in Colorectal Carcinoma

2003 ◽  
Vol 127 (6) ◽  
pp. 694-700 ◽  
Author(s):  
Valérie Rigau ◽  
Nicole Sebbagh ◽  
Sylviane Olschwang ◽  
François Paraf ◽  
Najat Mourra ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Protein Expression ◽  
Microsatellite Instability ◽  
Hereditary Nonpolyposis Colorectal Cancer ◽  
Screening Method ◽  
Molecular Testing ◽  
Cancer Syndrome ◽  
Simple Method ◽  
Mmr Genes ◽  
Hereditary Nonpolyposis

Abstract Context.—Microsatellite instability (MSI) due to defective mismatch repair (MMR) genes has been reported in the majority of colorectal tumors from patients with hereditary nonpolyposis colorectal cancer syndrome and in 10% to 15% of sporadic colorectal cancers. The identification of cancers associated with MSI requires classical molecular testing as the gold standard. Objective.—The aim of this study was to evaluate the role of immunohistochemistry with antibodies directed against 4 MMR proteins as a screening tool for carcinomas with MSI. Methods.—In this study, 204 formalin-fixed, paraffin-embedded colorectal carcinomas were examined for MMR protein expression (hMLH1, hMSH2, hMSH6, and hPMS2) and analyzed for MSI (MSI-H indicates at least 2 of 6 markers affected). These results were correlated with histopathologic parameters. Results.—Immunohistochemical analysis revealed that loss of expression of at least 1 protein was present in 17% of cases. One hundred percent of carcinomas that showed high instability (MSI-H) showed loss of expression of hMLH1, hMSH2, or hMSH6. Loss of expression of 2 proteins was present in 59.4% of MSI-H cases, with only 2 combinations, namely, hMLH1/hPMS2 and hMSH2/hMSH6. Isolated loss of hMSH6 expression was present in 2 MSI-H cases. Conclusions.—These findings confirm that examination of MMR protein expression by immunohistochemistry is a simple method to diagnose colorectal cancer with MSI. Our data suggest that the study of hMSH6 may be useful, in addition to hMLH1 and hMSH2. Moreover, immunohistochemistry could represent a screening method with which to direct research on the mutations of MMR genes observed in hereditary nonpolyposis colorectal cancer syndrome.

Immunohistochemistry Identifies Carriers of Mismatch Repair Gene Defects Causing Hereditary Nonpolyposis Colorectal Cancer

2005 ◽  
Vol 23 (21) ◽  
pp. 4705-4712 ◽  
Author(s):  
Astrid T. Stormorken ◽  
Inger Marie Bowitz-Lothe ◽  
Tove Norèn ◽  
Elin Kure ◽  
Steinar Aase ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Mismatch Repair ◽  
Hereditary Nonpolyposis Colorectal Cancer ◽  
Mismatch Repair Gene ◽  
Repair Gene ◽  
Predictive Values ◽  
Blood Samples ◽  
Bethesda Criteria ◽  
Amsterdam Criteria ◽  
Hereditary Nonpolyposis

Purpose Hereditary nonpolyposis colorectal cancer (HNPCC) may be caused by mutations in mismatch repair (MMR) genes. The aim of this study was to validate immunohistochemistry and family history as prescreening tools to predict germline mutations in MLH1, MSH2, and MSH6. Patients and Methods Pedigrees from 250 families were extended, cancer diagnoses were verified, and families were classified according to the Amsterdam and the Bethesda criteria. Tumor specimens were examined with immunohistochemistry for the presence of MLH1, MSH2, and MSH6 proteins. Mutation analyses were performed in blood samples from the same patients. Results Blood samples from affected index persons in 181 families and tumor specimens from 127 of the affected index persons were obtained. Thirty tumors lacked one or more gene products. Sensitivity of immunohistochemistry to detect mutation carriers was 100%, specificity was 82%, and positive predictive value was 85%. Sensitivities, specificities, and positive predictive values for the Amsterdam criteria were 82%, 8%, and 45%, respectively, and for the Bethesda criteria were 100%, 0%, and 48%, respectively. Distribution of mutations was MLH1 = 4, MSH2 = 11, and MSH6 = 4. Conclusion Wide clinical criteria to select HNPCC kindreds, followed by immunohistochemistry of tumor material from one affected person in each family, had high sensitivity and specificity to predict MMR mutations.

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