ABSTRACT
Chemical carcinogens can be divided into two categories, i.e., initiators and promoters, based on the two stage model of carcinogenesis. Most initiators can be detected by various genotoxicity tests, the results of which are used for carcinogenicity prediction (IARC/NCI/EPA Working Group, 1985). In the case of tumor promoters, several methods have been proposed (Fitzgerald, D.J. et al. 1989), but none of them have been routinely used for regulatory purposes. Therefore, developing a method for the detection of genotoxic and non-genotoxic carcinogens is a major challenge for the safety evaluation of chemicals. The utilization of additional screening tests covering a wide range of carcinogens has an advantage before contemplating in vivo long-term carcinogenicity experiments for chemical safety assessment.
