[Cancer chemoprevention-basic and clinical aspects].

Cancer chemoprevention is the use of agents to inhibit, delay or reverse carcinogenesis, and was proposed in the United States in view of the cost-benefits. Since recent progress in molecular biology revealed several signal transduction routes in carcinogenesis, the search for mechanism-based chemopreventive agents is under way. Many chemopreventive clinical trials for various cancers including colorectal cancer, prostate cancer and breast cancer, have been performed. Chemoprevention to eradicate viruses or bacteria such as hepatitis viruses or Helicobacter pylori is also important in order to prevent development of cancer.