Genetic polymorphisms may modify the effects of environmental risk factors on cancer occurence. We have recentlylaunched a comprehensive epidemiologic project, HERPACC II (Hospital-based Epidemiologic Research Programat Aichi Cancer Center II), including both lifestyle and polymorphism data, following HERPACC-I which solelyconcentrated on lifestyle data. As of April 2001, about 3000 samples of DNA are being stored to conduct case-controlstudies. Genotyping of 46 polymorphisms has been conducted at the laboratory of the Division of Epidemiology andPrevention. Twelve case-control studies and two papers on a new PCR method, PCR-CTPP (polymerase chain reactionwith confronting two-pair primers), have been accepted for publication. Significant findings in Japanese were foundfor 1) gene-environment interaction for esophageal cancer between heavy drinking and aldehyde dehydrogenase 2(ALDH2), 2) malignant lymphoma risk with methylenetetrahydrofalate reductase (MTHFR) and methionine synthase(MS), 3) interactions between smoking and two polymorphisms, interleukin 1B (IL-1B) and myeloperoxidase (MPO)for Helicobacter pylori infection, and 4) smoking habits with dopamine receptor D2 (DRD2) and IL-1B. Furtherstudies on interactions with polymorphisms will continue to be conducted for Japanese, using larger sizes of samples.