ABSTRACT
Cancer is a leading cause of death [8,162], and it can result from exposure to exogenous chemicals [359]; thus, in the toxicological assessment of chemicals, testing for carcinogenicity constitutes one of the most important evaluations and is required under numerous regulations or agreements (Table 25.1). A large database on the carcinogenic or oncogenic activities of chemicals in rodents has accrued [114,115,236] as a consequence of over 80 years of basic research and the output from national testing programs in several countries, particularly the United States and Japan. In the U.S. National Toxicology Program (NTP), routine rodent cancer bioassays (RCBs), mainly in mice and rats, have been reported for over 530 chemicals [244], and further testing is ongoing.
