Black-white differences in risk for cutaneous, ocular, and visceral melanomas

Fair-skinned individuals have a much higher risk of cutaneous and ocular melanomas than dark-skinned individuals, possibly reflecting a protective effect of melanin against sun exposure. There are some reasons to believe that the effect of sunlight exposure is indirect (i.e., sunlight stimulates growth factor production, which then stimulates melanocytic proliferation, leading to melanoma). Visceral melanomas are extremely rare, and little is known about them. This study used US data on 25,184 melanoma cases to investigate the White-Black ratio for visceral melanoma and did not find a disproportionality similar to that for cutaneous and ocular melanomas. The findings support the hypothesis that the sunlight effect on melanoma is primarily direct.