Melanocytes are the melanin -producing cells and they are scattered along the bottom of the epidermis. Every basal cell is attached to a melanocyte. There is one melanocyte per 10 to 20 basal cells. Melanin produced in the melanocytes is delivered to the basal skin cells. Paler-skinned people do not have fewer melanocytes than black people, but simply produce less melanin and a different kind of melanin per melanocyte.
Ultraviolet radiation stimulates the enzyme that makes melanin.
Melanomas are the deadliest skin cancers of all. They account for only about 5 per cent of cases but cause 80 per cent of skin cancer deaths. Melanomas can occur anywhere on the body. The important signs are either a new mole, a recent change in the size, shape or colour of an existing freckle or mole, or bleeding or tenderness of a mole. As it grows, a melanoma will eventually push beyond the epidermis of the skin, and then can spread throughout the body.