Cocarcinogenic and tumor-promoting capabilities of anthralin

Numerous chemicals to which humans are exposed either therapeutically or as a result of living in an industrial environment constitute a potential threat as carcinogens, mutagens, and/or tumor promoters and cocarcinogens. Anthralin, and antipsoriatic agent, acts as a tumor promoter for Balb/c-3T3 mouse embryo cell cultures that were previously exposed to a low dose of either benzo-a-pyrene (BaP), an indirect-acting carcinogen needing metabolic conversion for its carcinogenic action, or beta-propiolactone (BPL), a direct-acting carcinogen which needs no metabolic conversion. As a cocarcinogen, i.e., when exposure of cells to anthralin was simultaneous with exposure to the carcinogen, anthralin enhanced neoplastic transformation only when the carcinogen was BaP. Several explanations are explored. The possibility that cocarcinogens and tumor promotion occur by separate mechanisms is suggested.