A germ-line mutation of hMSH6 (also called GTBP) was found in a hereditary nonpolyposis colorectal cancer (HNPCC)-like patient in whom germ-line mutations of hMSH2, hMSH3, or hMLH1 had not been detected. The patient had rectal cancer and two colon adenomas at 62 years of age and a weak family history of gastrointestinal tumors, indicating atypical HNPCC. Somatic mutations of hMSH6 were observed in three colorectal tumors from the patient, indicating two-hit inactivation. Microsatellite instabilities at mononucleotide repeats were detected in all three tumors. These data suggest that hMSH6 is responsible for tumorigenesis in atypical HNPCC.
↵1 Supported in part by a Grant-in-Aid for Scientific Research on Priority Areas from the Ministry of Education, Science, Sports and Culture of Japan (to Y. A. and Y. Y.) and by a research grant from the Princess Takamatsu Cancer Research Fund (to Y. Y.).
↵2 To whom requests for reprints should be addressed, at Department of Hygiene and Oncology, Tokyo Medical and Dental University School of Medicine, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113, Japan. Phone: 81-3-5803-5182; Fax: 81-3-5803-0125; E-mail: [email protected]
- Received June 13, 1997.
- Accepted July 31, 1997.
- ©1997 American Association for Cancer Research.