The Induction of Melanotic Tumors Resembling Cellular Blue Nevi in the Syrian White Hamster by Cutaneous Application of 7,12-Dimethylbenz[a]anthracene*

Melanotic tumors resembling cellular blue nevi of man were induced in the Syrian white hamster by single and multiple applications of 7,1~-dimethylbenz[a]anthracene (DMBA). Histologically they resembled the melanotic tumors produced under similar experimental conditions in the Syrian golden hamster. They showed great variations in pigment content from almost nonpigmented to heavily pigmented tumors. Study of early lesions suggested origin of the melanotic tumors in the Syrian white hamster from amelanotic perifollicular melanocytes. None of the induced tumors metastasized. One of the poorly pigmented tumors was transplanted into both golden and white Syrian hamsters. One of the transplants gave rise to metastases to lymph nodes, lungs, and kidneys. The capacity to produce pigment was retained in the transplanted tumors. The study confirms our previous observation that cutaneous application of a single dose of DMBA to Syrian hamsters induces a high incidence of melanotic tmnors which differ morphologically and biologically from the melanomas known to occur spontaneously in the Syrian golden hamster.