Melanoma of the skin is not caused by ultraviolet radiation but by a chemical xenobiotic.

The putative ultraviolet (u.v.) carcinogenesis of cutaneous melanoma bears sufficient inconsistencies as to seriously challenge this theory. A more attractive hypothesis is the incrimination of a hitherto unknown chemical xenobiotic. This hypothesis explains the dramatic increase in incidence rates in most affluent countries during the last two or three decades. It also explains the particular risk of populations of high socio-economic status and the increased risk of indoor workers. It finally explains the urban-rural and coastal-inland trends observed in many countries with high incidence rates.