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About Skin Cancer

Skin cancer is the most common form of cancer in the United States. More than one million cases of skin cancer are diagnosed in the U.S. each year. In fact, it is estimated that 1 out of 7 people in this country will develop some form of skin cancer during their lifetime.

Skin cancer is a disease in which cancer (malignant) cells are found in the outer layers of your skin. Your skin protects your body against heat, light, infection and injury. It also stores water, fat and vitamin D. Since skin cancer generally develops in the epidermis, the outermost layers of skin, a tumor is usually clearly visible. This makes most skin cancers detectable in the early stages.

What Causes Skin Cancer?

Sun exposure is the leading cause of skin cancer. According to the American Cancer Society, “Many of the more than 1 million skin cancers diagnosed each year could be prevented with protection from the sun’s rays.” Scientists now know that exposure to the sun’s ultraviolet (UV) rays damages DNA in the skin. The body can usually repair this damage before gene mutations occur and cancer develops. When a person’s body cannot repair the damaged DNA, which can occur with cumulative sun exposure, cancer develops.

In some cases, skin cancer is an inherited condition. Between 5% and 10% of melanomas develop in people with a family history of melanoma.

Who Gets Skin Cancer?

Skin cancer develops in people of all colors, from the palest to the darkest. However, skin cancer is most likely to occur in those who have fair skin, light-colored eyes, blonde or red hair, a tendency to burn or freckle when exposed to the sun, and a history of sun exposure. Anyone with a family history of skin cancer also has an increased risk of developing skin cancer. In dark-skinned individuals, melanoma most often develops on non-sun-exposed areas, such as the foot, underneath nails, and on the mucous membranes of the mouth, nasal passages, or genitals. Those with fair skin also can have melanoma develop in these areas.

Bob Marley died of Melanoma

Bob MarleyThe legendary Bob Marley died from a cancer whose primary source was an acral melanoma under one of his toe nails. Rare but tricky to spot sometimes, Acral melanoma accounts for about 5% of all diagnosed melanomas. It is, however, one of the most common forms of melanoma in Asians and people with dark skin, accounting for up to 50% of melanomas that occur in people with these skin types. (And this is very important since recent studies have shown that Hispanics and African Americans tend to delay seeking diagnosis or treatment.)

Acral melanoma is often referred to as a “hidden melanoma” because these lesions occur on parts of the body not easily examined or not thought necessary to examine. It develops on the palms, soles, mucous membranes (such as the lining of the mouth, nose and female genitals) and underneath or near fingernails and toenails.

What does your ZIP code say about your risk for cancer? - CBS News

What does skin cancer, specifically melanoma, look like?


ABCDE’s of Melanoma

  • Asymmetry: One half doesn’t’ look like the other half
  • Borders: Uneven, notched or fuzzy
  • Color: More than one color or shade
  • Diameter: Greater than one-fourth of an inch
  • Evolving: If a mole changes size, shape or color

Palms of hand or soles of feet

Melanoma usually begins as an irregularly shaped tan, brown or black spot. It can be mistakenly attributed to a recent injury.

Under a nail

The first sign may be a “nail streak” – a narrow dark stripe under the nail. A new nail streak not associated with recent trauma, an enlarging nail streak, a wide or very darkly pigmented streak, or a nail that is separating or lifting up from the nail bed should be examined by a doctor. Acral melanoma can also develop without any obvious nail streak – particularly the non-pigmented variety.

Include these areas in your skin self-exams especially during a celebrity-style manicure or pedicure!

**Information reprinted from Molesafe's Melanoma Update.

Additional links and resources

Know your UV levels and risks with this UV Safety Poster.

Get the facts. The CDC has a great facts sheet about skin cancer skin cancer fact sheet (PDF).

The Dermatology Group (

Web MD (

eMedicine ( (