Abstract
Effect of the active tumor promoter, TPA, on the induction of hair follicular growth and possible neoplasia was studied histologically in normal nd precancerous mouse skin. Biweekly application of TPA resulted in nevoid proliferation of hair follicles, decreased the latent period of tumor induction, and increased the number of carcinomas of hair follicular origin in mice pretreated with MCA. The experimental tumor induction data was compared with human adnexal tumors of hair follicular origin. Similar types of animal and human lesions could be attributed to the promoter effect alone or to the dual influence of a carcinogen and promoter.