ABSTRACT
Skin cancer is the most common of all human cancers, with 1 million people in the U. S. diagnosed each year with some type of the disease. Like many cancers, skin cancers start as precancerous lesions. These precancerous lesions are changes in skin that are not cancer, but could become cancer over time. Medical professionals often refer to these changes as dysplasia.
There are three major types of skin cancers: basal cell carcinoma( BCC), squamous cell carcinoma( SCC), and melanoma. The first two skin cancers are grouped together as non-melanoma skin cancers. Other unusual types of skin cancer include Merkel cell tumors and dermatofibrosarcoma protruberans.
Melanoma is the most dangerous form of skin cancer, these cancerous growths develop when unrepaired DNA damage to skin cells( most often caused by ultraviolet radiation from sunshine or tanning beds) triggers mutations( genetic defects) that lead the skin cells to multiply rapidly and form malignant tumors. These tumors originate in the pigment-producing melanocytes in the basal layer of the epidermis. Melanomas often resemble moles; some develop from moles. The majority of melanomas are black or brown, but they can also be skin-colored, pink, red, purple, blue or white. Melanoma is caused mainly by intense, occasional UV exposure( frequently leading to sunburn), especially in those who are genetically predisposed to the disease. Melanoma kills an estimated 10,130 people in the US annually.
Both UVA and UVB rays are dangerous to the skin, and can induce skin cancer, including melanoma. Blistering sunburns in early childhood especially increase risk, but sunburns later in life and cumulative exposure also may be factors. People who live in locations that have more sunlight— like Florida, Hawaii, and Australia— develop more skin cancers, but some more northern locations with light-skinned populations also have a high number of skin cancers. Avoid using a tanning booth or tanning bed, since it increases your exposure to UV rays, raising your risk of developing melanoma and other skin cancers.