Relationship of Selenium to Cancer. I. Inhibitory Effect of Selenium on Carcinogenesis

Abstract

In 5 of 6 nondietary tumor-promotion experiments, sodium selenide significantly reduced the number of tumors in mice. In 2 of these 6 experiments, vitamin E also significantly reduced the number of animals with tumors. In all 6 experiments, both selenium and vitamin E decreased the total number of papillomas. Another antioxidant and 2 lysosomal stabilizers were ineffective. After 19 weeks of administration, sodium selenide did not significantly lower the number of mice with 3-methylchol-anthrene-induced papillomas nor after 30 weeks of administration did it reduce the number of cancers. Nonetheless, the total number of papillomas and cancers were greatly decreased. Torula yeast diets containing 1.0 parts per million (ppm) sodium selenite given to mice markedly decreased the number of skin tumors induced by 7,12-dimethylbenz[a]anthracene plus croton oil and benzo[a]pyrene. Torula diets containing 0.1 ppm sodium selenite and also a commercial diet (Rockland) did not decrease tumor incidence.