Nevi and melanoma induced by chemical carcinogens in laboratory animals: similarities and differences with human lesions.

The isolation of benzo(a)pyrene (BP) from coal tar, and the synthesis of dibenzanthracene (DBA), methylcholanthrene (MCA), and dimethylbenzanthracene (DMBA) in the 1930's, facilitated the induction of epidermal tumors in experimental animals. It was soon found that chemical carcinogens affect not only keratinocytes, but also the melanocytes (Szabo 1953). "Painting" the skin of small laboratory animals, with carcinogens, became the principal method of studying the mechanisms of chemical carcinogenesis (Yuspa et al. 1976a). Pigmented nevi and melanoma are perhaps two of the most interesting problems in dermatology, oncology and pathology. Questions related to histogenesis, classification, diagnosis, treatment and eventual prevention remain unanswered. A substantial amount of our work is used to support most of the main points regarding the development of nevi and melanoma in laboratory animals.