The main objective of this proposal is to obtain comparative data on the response of nonhuman primates to known rodent carcinogens as well as to suspected human carcinogens. Of particular interest is to evaluate in monkeys several chemicals of social and economic importance, such as DDT, saccharin, cyclamate and arsenic. Another objective is to evaluate the long term effects (including carcinogenicity) of antineoplastic agents which currently are in clinical use for primary and adjuvant cancer therapy and for chronic treatment of an increasingly broad spectrum of non-malignant diseases. Other objectives include obtaining tumor model systems in primates for use in testing the effectiveness of new antitumor agents, developing models and strategies for chemoprevention, and developing biological markers and diagnostic tests for early detection of malignant tumors.