MSH6 germline mutations are rare in colorectal cancer families

✍ Scribed by Paolo Peterlongo; Khedoudja Nafa; Gabriel S. Lerman; Emily Glogowski; Jinru Shia; Tian Z. Ye; Arnold J. Markowitz; José G. Guillem; Prema Kolachana; Jeffrey A. Boyd; Kenneth Offit; Nathan A. Ellis

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: French
• Weight: 404 KB
• Volume: 107
• Category: Article
• ISSN: 0020-7136
• DOI: 10.1002/ijc.11415

✦ Synopsis

Germline mutations in MSH6 can cause HNPCC, which is associated with a tumor phenotype featuring MSI. However, tumors arising in persons with disease-causing mutations of MSH6 may or may not exhibit MSI. We used D-HPLC to screen for germline mutations in the promoter region, the coding region and the 3'-UTR of MSH6. Eighty-four families, enrolled on the basis of Amsterdam I and II criteria (HNPCC families) and less stringent criteria (HNPCC-like families), were tested for MMR gene mutations; 27 families had a disease-causing mutation in MLH1 or MSH2, and the remaining 57 families were tested for mutations in MSH6. Two protein-truncating mutations were identified in each of 2 families fulfilling the Amsterdam I criteria, being present in persons affected with early-onset colorectal cancers exhibiting MSI. Immunohistochemical analysis showed that expression of both MSH2 and MSH6 proteins was lost in the cancer cells of the 2 mutation carriers but only MSH6 protein expression was lost in 2 adenomatous polyps. A third possibly disease-causing mutation was found in a person affected with a tumor that did not exhibit MSI. In addition, we found 4 new polymorphisms and determined that neither of the 2 studied by association analysis conferred susceptibility to colorectal or endometrial cancer. Altogether, our results indicate that disease-causing germline mutations of MSH6 are rare in HNPCC and HNPCC-like families.