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Skin Cancer Basics

If you or someone close to you has been diagnosed with skin cancer, basic information about the disease can be helpful in planning and understanding your treatment. When caught and treated early, 99% of skin cancers can be cured.

Mohs surgery is the most effective treatment for most types of skin cancer. To learn more about your options, find a fellowship trained Mohs surgeon in your area.

What Is Skin Cancer?

While normal skin cells grow, develop, and die in predictable cycles, skin cancer develops when skin cells grow out of control. Instead of dying, the damaged DNA within skin cancer cells causes them to continue growing and produce more abnormal cells. They also tend to invade other tissues. Skin cancer is the most common type of cancer in the US.

Causes of Skin Cancer

The primary cause of skin cancer is exposure to the ultraviolet (UV) light which damages the DNA with repeated exposure. People with chronic exposure to UV light, whether in the outdoors or in tanning booths, are at increased risk of developing skin cancer. The World Health Organization recently elevated tanning beds to its highest cancer risk category, the same rating it gives to cigarettes. Immuno-suppressed patients, such as organ transplant recipients or patients with chronic lymphocytic leukemia (CLL) are at greatly increased risk as well, because their immune systems are not as capable or warding off cancerous cells.

Skin Cancer basics model photo

Types of Skin Cancer

The skin is made up of several types of cells which can be affected by distinct types of skin cancer. The 3 most common types of skin cancer, which together make up approximately 99% of diagnosed cases, are basal cell carcinoma, squamous cell carcinoma, and melanoma. Mohs surgery can effectively treat all of these kinds of skin cancer. This section provides general descriptions of each type of skin cancer. In actuality, skin cancer can take on many variations and characteristics. If you experience any notable skin changes, consult with a dermatologist immediately. See skin cancer photos.

Basal Cell Carcinoma

As the most common type of skin cancer, basal cell carcinoma accounts for about 80% of all diagnosed skin cancers. It begins in the basal cells, which are skin cells located in the lowest layer of the epidermis. This type of cancer can look like a sore that doesn't completely heal, a shiny bump, or a reddish, irritated portion of the skin in an area that is exposed to the sun, such as the head, ears, face, shoulders and chest. It usually progresses slowly and does not tend to spread to other areas of the body (metastasize). Early detection and treatment can prevent basal cell carcinoma from spreading to surrounding tissue.

Squamous Cell Carcinoma

Potentially more aggressive than basal cell carcinoma, squamous cell carcinoma forms just beneath the surface of the skin in the squamous layer. While this second most common type of skin cancer often develops on sun-exposed areas, it can develop on other areas of the body like the mucous membranes and genitals. It often looks like a thick, rough, scaly patch or a bump. According to The Skin Cancer Foundation, more than one million Americans are diagnosed annually with squamous cell carcinoma.


The most dangerous of the common forms of skin cancer is melanoma. While it accounts for only about 3% of skin cancer cases, melanoma is responsible for over 75% of skin cancer-related deaths. The Skin Cancer Foundation estimates that more than 9,700 people will die from melanoma in 2017. Melanoma originates in pigment-producing cells called melanocytes, which give the hair, skin, and eyes their color. Melanomas are usually black or brown, and often develop in a mole or take on the appearance of a new mole. If identified early, cure rates for melanoma are quite high. Once melanoma spreads to other parts of the body, cure rates are significantly reduced.

While you can review details about skin cancer, it's important to have your skin regularly examined by a dermatologist. Make an appointment immediately if you find any suspicious areas. Learn about skin cancer symptoms and diagnosis.