Risk factors for the development of primary cutaneous malignant melanoma.

It is now possible to identify a small number of genes in which identifiable abnormalities are associated with an increased risk of melanoma, and a large number of phenotypic factors, which are associated with a lesser risk affecting a very much larger proportion of the melanoma population. As with colon cancer, it seems likely that there is a stepwise development of invasive malignant melanoma, and that interaction between genotype and environmental stimuli may be very different at each successive stage of melanoma progression. Unraveling these steps is the current challenge.