Melanoma is a form of skin cancer that arises from melanocytes. Melanoma is most common in Caucasians between 40 and 70 years of age. Explain why Caucasians would have a greater incidence of melanoma. Also explain exactly what the role of melanocytes are in the skin and why would they develop cancer more easily than other epidermal cells?
Melanoma is usually formed from DNA damage caused by too much exposure to ultra-violent light from the sun. Caucasians suffer a greater incidence of melanoma because they do not have as much pigmentation as other races and are, thus, more vulnerable to UV exposure. The tumors of melanoma originate in the pigment-producing melanocytes in the basal layer of the epidermis.
Melanocytes are cells that produce melanin in the lower level of the epidermis. the production of melanin is called melanogenesis, a process which leads to a long-lasting pigmentation that differs from pigmentation formed as a result of sun exposure. But, since melanogenesis and the "action spectrum" of sunburn are nearly the same, it is assumed that they are induced in the same mechanism. When UV rays penetrate the skin and damage DNA, fragments from this DNA can stimulate melanogenesis, causing the production of melanosomes which then are sent to the outermost layer of the skin. It is this damaged DNA reaction which poses the danger as it stimulates the production of melanin by melanocytes.