What Causes Melanoma?
The main cause of melanoma is from too much ultraviolet (UV) radiation (sunlight or tanning booths) reaching the skin. Excessive UV rays can damage skin cells, causing the cells to grow abnormally.In fair-skinned people, melanocytes make less melanin, so there is less protection against harmful UV radiation. Fair-skinned people have a higher risk for melanoma and other types of skin cancer if they have too much exposure to sunlight or tanning booths and sunlamps.
Some people may have a hereditary defect that increases their risk of melanoma. Ask relatives if there is a history of melanoma in your family.
Source: Melanoma.com