Skin cancer is the abnormal growth of skin cells. It may first appear as a new mole, a change in a growth or mole, a sore that does not heal, or an irritation of the skin.
Exposure to the sun is the most common cause of skin cancer. Problems with the body's defense system (impaired immune system) and a family history of skin cancer also increase a person's risk.
There are 3 major types of skin cancer:
Skin cancer is treated by removing the cancerous area with either surgery (excision) or freezing (cryotherapy). Chemotherapy and radiation therapy may be needed to treat an aggressive form of skin cancer or one that has spread to other parts of the body.
WebMD Medical Reference from Healthwise