Effect of Aging in Two-Stage Carcinogenesis on Mouse Skin with Phorbol Myristate Acetate as Promoting Agent¹

Life table analysis curves have been constructed for some of the data presented in a previous report on the effect of aging and of the interval between primary and secondary treatment in two-stage carcinogenesis on mouse skin. These curves are compared with those in a recent report from another laboratory also concerning aging and skin carcinogenesis. While comparison was difficult due to differences in experimental protocol, our conclusion that age at the onset of secondary treatment is of overriding importance in determining final tumor yields is substantiated.