One in five Americans will develop skin cancer in the course of a lifetime. There are new cases every year, more than incidences of breast, prostate, colon, and lung cancers combined. The three most common forms of skin cancer are basal cell carcinoma, squamous cell carcinoma, and melanoma. Skin cancer is the uncontrolled growth of abnormal skin cells. It occurs when unrepaired DNA damage skin cells that then trigger mutations that lead the skin cells to multiply rapidly and form malignant tumors.