Melanoma epidemiology, biology and prognosis

Melanoma is a cancer arising from the malignant transformation of melanocytes. These pigment-producing cells derive embryologically from pluripotent neural crest stem cells. During foetal development they not only predominantly migrate to and differentiate within the epidermis, but also to other extra-cutaneous pigment-containing sites such as the eyes, meninges, oesophagus and mucous membranes. Three subtypes of melanoma can therefore be characterised: cutaneous melanoma (the most common) arising from melanocytes in the epidermis, mucosal melanoma from melanocytes residing in the mucous membranes and uveal melanoma from melanocytes residing in the ocular stroma. In this chapter we will consider each of these melanoma subtypes in turn, highlighting the differences in epidemiology, biology and prognosis between them.