Melanoma is a type of skin cancer that arises from the cells that produce melanin (the pigment that gives skin its color). According to the American Cancer Society, about 54,200 new cases of melanoma will be diagnosed in the U.S. this year. About 7,600 people will die from it.
Although melanoma can occur at any age, it's most commonly diagnosed after 50. An important risk factor is excessive exposure to the sun. Sunlight contains ultraviolet radiation, which can damage skin cells. The damage appears to be most associated with periods of intense exposure. Severe, blistering sunburns during childhood or adolescence can greatly increase the risk for melanoma. People with fair skin, freckles, and light hair are at higher risk for sunburns and development of the cancer. The presence of many atypical moles (called dysplastic nevi) is also associated with increased risk.
Melanoma can be very serious because the cancer can quickly invade underlying tissue, eventually reaching the lymph system and spreading to other parts of the body. However, if the disease is diagnosed and treated early (while its still confined to the outermost layer of the skin), cure rates are nearly 100 percent. Health experts recommend regular skin self-exams to find skin abnormalities at early stages. The ABCD rule is often used to remember the signs of melanoma:
In addition to the ABCD rule, look for moles that change in size, shape, color, elevation or surface texture.
Melanoma and PTEN
PTEN (phosphatase and tensin homologue) is a gene that controls cell death. When a normal cell malfunctions or is damaged, the gene expresses a protein that starts a chain of events leading to cell death. Researchers have discovered that many melanoma cells somehow turn off PTEN. That enables the abnormal cancer cell to continue to survive and grow. Eventually, scientists hope to be able to use gene therapy to place the PTEN gene back into the cancer cells. Then potentially, the cancer cells could be killed through chemotherapy.
Researchers say PTEN is lost or inactivated in 30 to 60 percent of melanomas. That means many other genes or proteins are involved in cancer cell survival. So scientists will continue to study the genetic aspects of cancer cells and perhaps find better treatments to stop the cancer in its tracks.