Skin cancer is the uncontrolled growth of abnormal skin cells. It occurs when unrepaired DNA damage to skin cells (most often caused by ultraviolet radiation) triggers mutations, or genetic defects, that lead the skin cells to multiply rapidly and form malignant tumours. Among the several types of skin cancer are melanoma, basal cell carcinoma, and Merkel cell carcinoma. Of the several types of skin cancer, melanoma causes the majority (75%) of deaths. In 2012, melanoma occurred in 232,000 people and resulted in 55,000 deaths worldwide. Melanocytes are the type of skin cells that produce melanin, a brown pigment that protects the skin from some of the...Read more » harmful effects of the sun, and they can become melanomas. The majority of melanomas are black or brown, but they can also be skin-colored, pink, red, purple, blue or white. Basal cell carcinoma (BCC) is a type of cancer that begins in the lower part of the epidermis (the outer layer of the skin). It may appear as a small white or flesh-colored bump that grows slowly, and bleeding may occur. BCC is the most common human cancer with 3.5 million cases diagnosed worldwide every year, of which about 0.8% of cases are locally advanced. When detected early the vast majority of cases are successfully managed through surgery, with 5-year cure rates exceeding 90%. Although rare, BCCs have the potential to progress to locally advanced and even metastatic disease. These cutaneous malignancies are often not treatable with surgery or radiation therapy. Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer that is at high risk of recurring and spreading (metastasising) throughout the body. Merkel cell carcinomas are usually curable when detected and treated at an early stage but they are often aggressive and can advance rapidly. These tumors usually appear as firm, painless lesions or nodules on a sun-exposed area. They are typically red, blue, purple or skin-colored and vary in size.