[Molecular biological assessment of susceptibility to colorectal cancer]

There are two entities in the predisposition for colorectal cancer. One is the hereditary colorectal cancers which include familial adenomatous polyposis (FAP), hereditary nonpolyposis colorectal cancer (HNPCC), and others. In the case of these hereditary diseases, genetic testing to detect germline mutation in the causative gene in family members is useful for identifying possible gene carriers. For the diagnosis of HNPCC, the present clinical criteria are not sufficient and analysis of DNA replication error (RER) could be useful. Another entity is genetic sensitivity to environmental carcinogens. In particular, the polymorphism of the genes encoding drug-metabolizing enzymes has been shown to be important in recent years. The fast acetylator genotype of N-acetyltransferase (NAT) genes and the null genotype of the glutathione S-transferase M1 gene have been reported to be associated with increased risk of colon cancer. In the strategy against colon cancer, it is extremely important to identify high-risk individuals so that we can prevent cancers or detect them in earlier stages.