By the year 2000, an American's lifetime risk of developing melanoma will be one in 75. Over the past two decades, the incidence of malignant melanoma in Caucasians increased at a faster rate than that of any other cancer, with the number of cases doubling. The incidence rate is rising most rapidly in persons below the age of 40, and the disease is now the most commonly occurring cancer in women between the ages of 25 and 29. The mortality rate for the disease has been increasing as well, with 7,300 melanoma related deaths now occurring a year. Excessive exposure to the sun activates melanin, causing skin to darken or tan as a protective measure.
Melanocytes are the cells in the skin that produce melanin, the pigment that gives skin color.
Melanomas can also form on areas of the body that are not exposed to the sun or are exposed only intermittently. If untreated, melanoma can spread or metastasize from the surface of the skin to internal organs. There is no single reason why a person gets cancer, yet certain risk factors are associated with malignant melanoma. A family history of melanoma is another risk factor. Certain moles, called atypical moles or dysplastic nevi , are more likely to become malignant than others, and an overabundance of these hereditary moles can also increase the risk of melanoma.