What Is Melanoma?
Melanomas are cancerous (malignant) tumors involving specialized cells called melanocytes. Melanocytes have the unique ability to produce the pigment melanin and can be found in the skin, mucous membranes, eye, adrenal gland, and brain. Melanomas have a peculiar tendency to spread to distant sites (metastasize) at an early stage of growth and to grow in an uncontrolled fashion at the new site. This results in organ damage and ultimately death. When melanoma spreads from its original site, it is referred to as metastatic melanoma. The incidence of this type of cancer has recently been rising and it is the single most common cause of death from any skin disease.
What Causes Melanoma?
Like most cancers, the cause of melanomas involves interplay between genetic and environmental factors. It is generally agreed that ultraviolet-light-induced mutations in melanocytes is the single most important environmental factor in the induction of cutaneous melanomas. The fact that melanomas are difficult to produce experimentally as well as their appearance in areas of the body in which no light exposure occurs has fueled some controversy as to causation. Melanomas tend to occur on sun-exposed skin in lightly pigmented individuals. On the other hand, there is a correlation between exposure to sunlight as defined by the earth's latitude and the incidence of melanoma. For example, melanoma is much more common in sunny areas, such as Arizona, than in Seattle. About 20% of melanomas are produced by heritable genetic mutations. Some of these genes have been identified. The remainder seem to be due to ultraviolet light-induced changes in genes (mutational events).
Medically Reviewed by a Doctor on 11/20/2017
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