[Familial aggregation of gastric cancer].

Pursuit of the etiologies of familial aggregation of gastric cancer is a particular challenge in an endemic area like Japan. A typical case having truncation-type CDH1 germline mutation, which constitutes an entity of hereditary diffuse gastric cancer, has never been found in Japan or Korea. In addition to candidate gene approaches, painstaking efforts are now in progress using several genome-wide approaches including genome-wide association studies which require a few replications of several thousands of cases and controls. Gene-environmental interactions are also determined to find out the attributes for gastric cancer predisposition.