Many skin and eye melanomas are thought to occur as a result of exposure to ultraviolet (UV) light. UV light comes from the sun and indoor tanning beds or booths. Doctors believe that repeated exposure to UV rays can damage the DNA in melanin (the skin’s pigment-producing cells), giving rise to cancer cells. However, not every melanoma is linked to a history of sun exposure or tanning bed use. Researchers are still working to understand the causes of these rare cancers. Learn more about melanoma risk factors.