Production of Melanomas From DMBA-Induced “Blue Nevi” in Hairless Mice With Ultraviolet Light<xref ref-type="fn" rid="FN2">2</xref>

Abstract

The effects of chronic low-dose mid-ultraviolet (UVL) exposures on benign blue nevi were examined in pigmented hairless mice. The benign growths were produced by a single application of 7,12-dimethylbenz[a]anthracene (DMBA). In this study, large invasive melano-cytic tumors were produced by the UVL in 5 of 18 animals. Apparent seeding of regional lymph nodes with tumor cells was a consistent feature of the melanomas. No distant metastasis was noted. No similar growths occurred spontaneously or in control groups receiving DMBA or UVL alone. Histologic, electron microscopic, and autoradiographic studies established that the tumor was composed of functioning neoplastic melanocytic cells. It was suggested that the system could serve as a model for evaluation of factors influencing melanoma formation.