What Is Skin Cancer?

With more than 2 million cases diagnosed every year in the United States alone, skin cancer is the most common cancer in the world. Skin cancer is the uncontrolled growth of abnormal skin cells. Normally, your DNA helps regulates how your skin cells grow. If that DNA is damaged, it can trigger mutations that can lead to cancerous tumors. Left untreated, these cancerous cells can spread and damage surrounding skin tissue. In the case of melanoma, it can even spread to vital organs and become life threatening.

The Sun and Skin Cancer

Most often, skin cancer is found on skin exposed to the sun. This is because the ultraviolet radiation from the sun and tanning beds causes the damage to your DNA. Skin cancer typically occurs where sun damage has been accumulated over time.

Sun exposure can lead to skin cancer in multiple ways. When exposed to UV radiation, your immune system works hard to try to repair the damage. However, when that DNA goes unrepaired, skin cancer occurs. This is why each time excessive exposure to the sun occurs, you increase your odds of developing skin cancer.

Sometimes, the sun exposure results in sunburn. When you get a sunburn, your skin cells have sustained damage and becomes inflamed from the overexposure to the sun. Sunburns increase the risk of developing skin cancer later in life. However, your skin cells can be damaged even if you do not get a sunburn (if you start tanning, it is a sign that sun damage has already occurred).

Luckily, skin cancer is very preventable and if caught early, one of the most curable. Make sure to always take precautions to protect yourself daily. You should check your skin monthly at home for warning signs of skin cancer. The most common warning sign is any change to your skin. See a dermatologist if you notice any of the following:

  • New growths or moles
  • Existing growths that start changing or growing
  • Growth or lesion that itches or bleeds
  • New lesions that are not healing

Types of Skin Cancer

There are several different kinds of skin cancers, distinguished by the types of cells affected. The three most common forms of skin cancer are:


BCC is the most common cancer, developing in more than one million people each year in the United States. Most skin cancers are BCC, which develops in the basal cells - the cells that make up the lowest layer of the skin. BCC may appear as a shiny translucent or pearly nodule, a sore that does not heal, a pink slightly elevated growth, reddish irritated patches of skin, or a waxy scar. It is most common on skin that has been exposed to the sun, like the face, ears, scalp, and upper trunk. While these tumors very rarely spread to other parts of the body, early diagnosis and treatment is necessary to prevent extensive damage to surrounding tissue.


SCC begins in the squamous cells, which are found in the upper layer of the skin. It is less common that BCC, with about 200,000 cases reported each year in the United States. It may appear as a crusted or scaly area of skin with a red inflamed base that resembles a growing tumor, non-healing ulcer or crusted-over patch of skin. While it usually appears on areas of the body that are exposed to the sun, it can develop anywhere, including the inside of the mouth and the genitalia. SCC requires early treatment to prevent it from spreading to other areas of the body.


Melanoma begins in the melanocytes, the cells that give skin its color. Melanoma is the deadliest form of skin cancer because it can rapidly spread to the lymphatic system and internal organs. Approximately one person dies from melanoma every hour. With early detection and proper treatment, the cure rate for melanoma is almost 100 percent. Once it spreads, the cure rate drops.

Source: American Society for Dermatologic Surgery
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