Melanoma induction in a hairless mouse with short-term application of dimethylbenz[a]anthracene

Melanomas have been induced in hamsters and guinea pigs with short-term, low dose applications of dimethylbenz [a]anthracene (DMBA) alone. In mice, however, melanoma induction has required either croton oil or ultraviolet radiation promotion in addition to DMBA. In this study, we report the development of a malignant melanoma, with metastases, in a hairless mouse after six applications of 0.25% DMBA alone. At sacrifice, a large primary tumour with characteristics of intralesional transformation was present, along with numerous pigmented macules and papules. Metastases were present in lymph nodes and lungs. There was a marked similarity between this melanoma and its precursor lesions and those seen in an earlier, Weiser-Maple guinea pig model, which, in turn, resembled human melanoma. (C) 2001 Lippincott Williams & Wilkins.