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Skin cancer is the most common form of cancer in the United States. Skin cancers can occur on any part of the body, though they most often occur in skin that is exposed to sunlight, especially the head and neck areas.

Skin cancers originate in the upper-most layer of the skin. They can then grow downward, forming finger-like projections under the skin’s surface. At times, these “roots” are subtle and can be seen only with the help of a microscope. Therefore, what you see on your skin is sometimes only a small portion of the total tumor (like seeing only the tip of a large iceberg).There are several forms of skin cancer, including:

Basal cell carcinoma: This skin cancer begins in the basal cells of the skin, which are responsible for creating new skin cells.

Squamous cell carcinoma: This skin cancer starts in the squamous cells that are located just below the outer surface of your skin.

Merkel cell carcinoma: A rare but very aggressive type of skin cancer that mainly affects older people who have a weakened immune system or who have had long-term exposure to the sun.

Melanoma: A type of skin cancer that affects cells called melanocytes, which create the pigment that colors skin. Although not the most common skin cancer, it is a form that is more likely to spread to other tissues and other parts of the body if not diagnosed and treated at an early stage. Melanoma can occur on any part of the skin, but is most common on sun-exposed areas. On rare occasions, it can occur on the mucosal surface or back of the eye. Melanoma accounts for about 2 percent of all skin cancer cases, but by far the majority of skin cancer deaths.

Risk Factors

There are many factors that can increase the risk of developing skin cancers, including:

  • Exposure to ultraviolet (UV) radiation. Common sources of UV radiation include sunlight, tanning beds and sun lamps.
  • Having a fair complexion, skin that freckles or burns easily, or light-colored hair.
  • Weakened immune system.
  • Older age.

Risk factors for melanoma also include:

  • Personal and family history of melanoma.
  • Atypical, large or numerous moles.
  • Having a history of blistering sunburns.


To reduce your risk of skin cancer, limit your exposure to UV radiation: 

  • Avoid tanning indoors or outdoors.
  • Use a broad-spectrum sunscreen throughout the year with a Sun Protection Factor (SPF) of at least 30 and that offers UVA and UVB protection.
  • Spend time outdoors when the sun’s rays are less intense — generally before 10 a.m. and after 3 p.m.
  • Wear sunglasses that offer UVA/UVB protection.

More tips for preventing skin cancer.

It is also important to check your skin regularly for signs of skin cancer. Be alert to changes in your skin or in moles you may already have. Here are some tips for checking your skin at home.