Exposure to ultraviolet radiation from tanning beds and lamps, as well as the sun, is the primary cause of melanoma, according to Mayo Clinic. Other causes include a combination of genetic and environmental factors.
When damage influences the way the melanin-producing cells in the skin operate, new cells can start growing out of control and creating a group of cancerous cells, according to Mayo Clinic. Normally, new skin cells push older cells up closer to the surface of the skin, where they die and fall away. However, DNA damage in some cells can lead to uncontrolled reproduction and therefore melanoma.