Modification of photocarcinogenesis by two immunosuppressive agents.

The carcinogenic effect of ultraviolet radiation (UVR) on the skin of hairless (hr) mice was modified by two immunosuppressive agents, rabbit anti-mouse lymphocytic serum (ALS), and 6-mercaptopurine (6MP). Daily exposure of mice to UVR resulted in multiple tumor production. Carcinogenesis was measured in terms of affected mice (prevalence) and numbers of tumors produced. By both criteria, photocarcinogenesis was enhanced by ALS but inhibited by 6MP.