Abstract
The Japanese Society for Cancer of the Colon and Rectum started the HNPCC registry and genetic testing project in September 2002. This project enrolled patients who met the modified Amsterdam II criteria including gastric cancer as an HNPCC-related tumor. The HNPCC patients registered in this project corresponded to approximately 2.1% of all colorectal cancer patients in the collaborating hospitals. We further carried out gene testing in 85 patients who gave informed consent to the analysis. Among the colorectal tumors arising in the HNPCC patients, those located in the right colon comprised 47.9%, and mucinous carcinoma comprised 8.4%, which were both significantly higher incidences than those in sporadic colorectal tumors. We searched for mutations of MSH2, MLH1, and MSH6 genes, and identified pathogenic mutations in approximately 54% of the probands. These data should contribute to a better understanding of the characteristics of Japanese HNPCC, and useful for Japanese HNPCC patients and their family members by facilitating a correct diagnosis and providing information about the disease.
