RESUMEN
Present study evaluates the chemopreventive actions of tamoxifen (10 mg/kg), retinyl acetate (50 mg/kg), tocopherol (200 mg/kg), aminoglutethimide (1 mg/kg), ergocryptine (5 mg/kg), and sodium selenite (1 mg/kg) when given singly/in combinations on the initiation of mammary carcinogenesis induced by 20 mg of DMBA in virgin female rats. DMBA was given when rats were 50 days old and the modulators were given in diet 10 days before and 10 days after carcinogen treatment and experiments were terminated 6 months later. DMBA alone yielded tumors in 62% rats. When modulators were given singly and in combinations of two, tumor incidences were not altered significantly. The range of tumor incidences was between 30% and 13% when the agents were given in combinations of 3, 4 and 5. Finally when all 6 modulators were given together the tumor incidence dropped down to 8.3%.