Causes of
MelanomaLike most cancers, the cause of melanoma involves interplay between genetic and environmental factors. It is generally agreed that ultraviolet-light-induced mutations in melanocytes is the single most important environmental factor in the induction of cutaneous melanomas. The fact that these cancers are difficult to produce experimentally as well as their appearance in areas of the body in which no light exposure occurs has fueled some controversy as to causation. Melanomas tend to occur on sun-exposed skin in fair-skinned individuals. On the other hand, there is a correlation between exposure to sunlight as defined by the earth's latitude and the incidence of melanoma. For example, melanoma is much more common in sunny areas. About 20% of melanomas are produced by heritable genetic mutations. Some of these genes have been identified. The remainder seem to be due to ultraviolet light-induced changes in genes (mutational events).