title: [Development of antitumor agents: retrospection and perspective].
abstract: A concept of antitumor screening with rodent tumor models is discussed through the experience in the past 30 years, together with an introduction of a new system of antitumor screening in NCI, U.S.A., including a recently adopted mouse ovary tumor model. It is suggested that the more minute and elaborate studies of mode of action of the effect and toxicity of the antitumor drugs which are already clinically evaluated are useful to get new structures of compounds with antitumor activity into our minds. A new approach in studying drug resistance of tumor cells proposed by Ling is introduced that some of the acquired drug resistance is closely related to natural resistance of tumor cells which occurs by spontaneous mutation of the cells during proliferation.
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000302:isolation & purification / Q000494:pharmacology* / Q000627:therapeutic use; D004353:Drug Evaluation, Preclinical / Q000379:methods / Q000639:trends; D004351:Drug Resistance; D006801:Humans; D008727:Methotrexate / Q000494:pharmacology; D051379:Mice; D009369:Neoplasms / Q000188:drug therapy
chemical_list: D000970:Antineoplastic Agents; D008727:Methotrexate