Skin cancer is the most common type of cancer in the United States. There are three common types of skin cancer: basal cell carcinoma, squamous cell carcinoma, and melanoma. Basal cell carcinoma is slow growing and rarely spreads. It affects the basal cells found in the second layer of the skin. Squamous cell carcinoma rarely spreads and affects the squamous layer of cells, found on the outermost layer of the skin. Melanoma affects the deepest layer of the skin, specifically the melanocytes, and is the most likely to spread, affecting deeper tissues of the body.
			Introduction
			Diagnosis
			Prevention
								Ultraviolet light is the primary cause of skin cancer. Exposure to natural UV light from the sun and artificial UV light, from sources such as tanning beds, increase the risk of developing cancer. The degree and duration of exposure increases the risk. This means that older individuals with a longer history of exposure are more likely than younger people, who have been exposed less, to develop cancer. Exposure during high-intensity sunlight hours, typically between 10am and 4pm, increase the risk. Populations at the greatest risk are those in areas that have high UV exposure and low ozone concentration in the atmosphere. People with light skin and freckles are more likely than dark-skinned people to develop cancer.
			Treatments
									Skin cancer usually involves a visible change in the skin. A doctor should examine an abnormal growth, a sore that doesn't heal, or changes in an existing mole or growth, as these are all possible symptoms of skin cancer. Skin cancers are not usually painful. The site of cancer may appear as shiny, pale, waxy, rough, scaly, or discolored. Basal and squamous cell carcinoma generally occur in areas of the skin often exposed to the sun. However, skin cancer can occur anywhere. Melanoma is usually signified by the ABCD guidelines. Asymmetrical moles, when one-half does not match the other, a ragged or unusually shaped boarder, uneven coloration, and changes in mole diameter are moles that should be brought to the attention of a physician.