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What is melanoma?

Graphic of the epidermisSkin cancer is the most common cancer diagnosed in the United States. Melanoma is the least common form of skin cancer, but it is also the most serious. While only 4% of all skin cancers are melanoma, it causes 75% of skin cancer deaths. Photo source: National Cancer Institute, Don Bliss

Melanoma starts with uncontrolled growth in the cells that make skin pigments. Those cells are called melanocytes and are located in the base of the skin's top layer, called the epidermis. When your skin darkens from tanning, you are seeing the increased production of melanin by melanocytes as they protect your skin's deeper layers from the sun. When melanocytes become cancerous, they appear on the skin as a new, or changing, pigmented spot or raised, discolored skin lesion.

The majority of melanomas begin in the skin, but they may occur in other sites such as the eyes, mucous membranes, digestive system, urinary tract, and the innermost layers of the tissues that surround the brain and spinal cord (meninges).

While fair skinned people are more likely to develop melanoma, it can affect people of all skin colors. The number of new melanoma cases has been increasing over the last 30 years. From 1982 to 2011, the rate of melanoma in Americans doubled, according to the Centers for Disease Control and Prevention. More than 65,000 people were diagnosed and over 9,000 people died of melanomas of the skin in the U.S. in 2012.

Avoiding sun exposure and tanning beds is the best way to prevent melanoma. For people who develop melanoma, surgically removing the lesion is typically the first treatment option. The prognosis for melanoma is much better if the cancer is caught early. That is why it is important to understand your risk for melanoma and what skin changes could be signs of melanoma.

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