Cancerous growths on the surface of the skin are known as skin cancers. Certain mutations in the DNA of these skin cells is held responsible for skin cancer. Such mutations are known to result in uncontrolled growth of the skin cells. These cancerous growths have the potential to spread to other parts of the body and cause havoc.

Skin cancer is of three kinds: basal cell cancer (BCC), squamous cell cancer (SCC) and melanoma. BCC and SCC are also called nonmelaoma skin cancer. Incidence of skin cancer can be checked by limiting exposure of skin to direct sunlight or ultraviolet radiation. 

Exposure to ultraviolet radiations of sunlight are the most likely causes of skin cancer. Theses radiations are responsible for the mutations that result in overgrowth of skin cells. The parts of the body normally  exposed to the sun are most likely to develop skin cancer. But parts of the body hardly ever exposed to the sun or light like the genitals are also likely to develop skin cancer. This way, contact with toxic substances is also likely to cause skin cancer.

Skin cancer is likely to occur in anyone regardless of the race or colour of the skin. But those deficient in melanin content in skin cells are more likely to develop skin cancer. Those with a tendency to develop  freckles on the face or those who sunburn easily are more likely to be diagnosed with skin cancer. 
The skin should be regularly inspected for irregular changes. If diagnosed at an early stage, skin cancer is likely to be treated at an early instance through medication or other therapy.