Incidence of Squamous Cell Carcinoma in Hairless Mice Irradiated with Ultraviolet Light in Relation to Intake of Ascorbic Acid (Vitamin C) and of D, L-a-Tocopheryl Acetate (Vitamin E)

Summary: We have carried out a study of large malignant skin tumors (squamous-cellcarcinomas) and other lesions in `hairless" mice (in groups of 45 or 60 mice) intermittentlyexposed to ultraviolet light over a period of 15 weeks, beginning when themice were about 8 weeks old. Various groups were given a standard diet (WayneLab-Blox) or the same food with added vitamin C or vitamin E throughout the study.Lesions, classified by histopathologic study as atypical squamous-cell proliferationsvaryingfrom early actinic keratoses to invasive poorly differentiated squamous-cellcarcinomas, had begun to develop by the end of the period of irradiation. They werecounted twice a month for five months. The observed fraction of mice that developedlesions during successive time periods was analyzed by the statistical method recommendedby a committee of the International Agency for Research on Cancer. Apronounced effect of vitamin C in decreasing the incidence of the malignant lesionswas observed with very high statistical significance. No significant effect of vitamin Ewas observed. We conclude that vitamin C should be given especial attention withrespect to the relation between diet and cancer_