Nonsolar factors in the etiology of malignant melanoma.

Although epidemiological evidence supports the role of solar radiation in the etiology of cutaneous malignant melanoma (MM) among Caucasians, solar exposure alone cannot explain all the epidemiological patterns of MM. This cancer can arise from both noncutaneous and cutaneous sites not exposed to the sun. Evidence is lacking for the involvement of solar exposure in the etiology of most MM among non-Caucasians. Moreover, among Caucasians, skin pigmentation and other genetically determined factors appear to be important in the risk of MM. Trauma, dietary factors (particularly retinoids), hormone factors, occupational exposures, viruses, and drugs can also influence risk. Future investigations of these and other factors among Caucasians must be designed for control of potential confounding by solar exposure and genetically determined susceptibility. Epidemiological studies of MM among non-Caucasians would be useful in the identification of risk factors other than solar radiation.