What Causes Melanoma?

The main cause of melanoma is too much ultraviolet (UV) radiation reaching the skin. UV rays from the sun and other sources (such as tanning booths) can damage skin cells, causing the cells to grow abnormally.

Melanin, the pigment that gives skin its color, protects the skin from damage by sunlight and UV rays. In fair-skinned people, the skin cells called melanocytes make less melanin, so there is less protection against the harmful rays from the sun. Fair-skinned people have a higher risk for melanoma and other types of skin cancer if they have too much exposure to sunlight.

Melanoma is also more common in people who live in areas with large amounts of UV radiation from the sun, such as the Southwestern United States.

Tanning booths and sunlamps also use UV light. These artificial sources of UV light can damage skin cells and increase the risk of melanoma.

Some people may have a hereditary defect that increases their risk of melanoma.

Glossary

Melanin: A dark-brown to black pigment found in the skin, hair, and parts of the eyes.
Melanocytes: Pigment-producing cells located in the epidermis.
Melanoma: A highly malignant type of skin cancer that arises in melanocytes, the cells that produce pigment. Melanoma usually begins in a mole.
Ultraviolet Radiation: Invisible rays from the sun. UV radiation can burn the skin and cause melanoma and other types of skin cancer. UV radiation that reaches the earth's surface is made up of two types of rays: UVA and UVB. UVA rays pass deeper into the skin and UVB rays are more likely to cause sunburn. Both kinds of radiation are believed to cause skin cancer and cause premature aging of the skin. People should use sunscreens that block or absorb both kinds of UV radiation.