Suppression of the promoter effect of polyunsaturated fatty acids by the absence of dietary vitamin E in experimental mammary carcinoma

Because lipoperoxides seem able to modulate tumor growth, we have examined the concomitant effects of dietary antioxidant (vitamin E) and of a high amount of polyunsaturated fatty acids (PUFA) in a model of chemically-induced mammary carcinogenesis. Two groups of rats received a high fat diet with or without added vitamin E and mammary tumors were initiated in both groups by an injection of carcinogen. Tumor growth was followed in both groups. We found that tumor incidence and growth were decreased in rats with no added vitamin E in diet, suggesting a protective role of oxidized PUFA at later stages of carcinogenesis.