[Hereditary site-specific colon cancer--report of two families].

Five cases of hereditary site-specific colon cancer (HSSCC or Lynch syndrome I) from two families are reported. The main features of HSSCC are: an autosomal dominant model of heredity, the absence of associated polyposis, the average age being younger, vulnerable site being the right colon (4/5 cases), multiple colon cancers (3/5 cases) and long survival. These 5 cases possessed the above mentioned features. Having no special detection method, the authors suggest that the members of these families be registered and the high risk members regularly checked.