Etiologic related studies of ultraviolet light-mediated carcinogenesis.

Comparisons were made of cholesterol-5alpha, 6alpha-epoxide (CAE) levels in skin of hairless mice maintained on a regular or antioxidant supplemented diet and receiving chronic ultraviolet light (UVL) radiation over an 18-week period. Cholesterol-5alpha, 6alpha-epoxide levels in skin of animals on antioxidant supplemented diet, while reaching a peak four weeks after that of animals on regular diet, thereafter were consistently higher. Dietary antioxidants nevertheless had an inhibitory effect on UVL-induced tumors. These data are inconsistent with the theory of CAE involvement as an ultimate carcinogen in UVL-mediated carcinogenesis.