Carcinogen-induced cutaneous neoplasms in nonhuman primates

Dimethylbenzanthracene (DMBA) combined with UV light, dodecylbenzene (DDB), or both was oncogenic when applied to the skin of nonhuman primates. Ten years after the cutaneous application of DMBA and a cocarcinogen, 2 groups of rhesus monkeys (Macaca mulatta) displayed dermal melanosis, papillomas, basal cell tumors, and mesodermal sarcomas (accompanied in one case by hepatic metastasis). One group had been painted for 15 months; the other, for 6 1/2 years. Eight years after the initiation of a 4-year regimen of biweekly applications of DMBA plus a cocarcinogen, papillomas, basal cell tumors, and basosquamous cell epidermal tumors with satellite lipomas were observed in galagos (Galago crossicaudatus). The same carcinogen applied to the skin of pottos (Perodicticus potto) caused death in 6 of the 7 animals within 9 weeks. Neoplasms occurred in 17 of the 19 primates that lived longer than 9 weeks after the cutaneous application of DMBA combined with either UV light or DDB.