What's Melanoma?

Melanoma of the skin. CREDIT: Skin Cancer Foundation View full size image

Melanoma is a type of skin cancer that develops from melanocytes, which are one type of cell found in the skin. The job of melanocytes in healthy people is to produce melanin, a brown pigment that protects the skin from sun damage by absorbing ultraviolet rays and affects skin color, according to the Mayo Clinic.

Human skin is made of two layers – the outermost layer is the epidermis, and the dermis lies beneath it. Most of the cells found in these layers are called keratinocytes, which do not produce any pigment. Without the melanocytes that are found in both layers of skin, dispersed throughout the skin's other cells, skin would be very light in color.

During normal aging, melanocytes proliferate and form clusters that can appear as age spots or moles. But if these cells begin to divide uncontrollably, the skin develops spots heavy with brown pigmentation. These spots are called melanomas, and they are cancerous.

Although melanomas can resemble normal moles, they are different from moles in a few ways. Melanomas can have an asymmetrical or irregular shape, a notched or scalloped border, or uneven coloration. In addition, they may grow in diameter or change in their color or shape, according to the Mayo Clinic.

In 2006, the most recent year for which statistics are available, 53,919 people were diagnosed with melanomas of the skin, and 8,441 people died from it, according to the Centers for Disease Control and Prevention (CDC). Other types of skin cancer, that develop from keratinocytes rather than from melanocytes, are less deadly.

The CDC recommends using sun screen, wearing sun glasses, and reducing skin exposure to the sun as ways to reduce your chances of developing this cancer.

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