What is Skin Cancer?

Written by: SERO Staff

Skin cancer occurs when certain types of cells in your skin become damaged, causing them to grow uncontrollably and form tumors.

Every cell in your body contains a microscopic molecule called deoxyribonucleic acid (DNA). DNA contains basic genetic instructions that tell your cells how to function. These instructions govern how your cells behave, grow, and reproduce.


Skin cancer forms when the DNA in your skin cells becomes damaged.

This damage may be caused by:

  • Exposure to harmful substances, such as UV radiation from the sun
  • Genetic mutations inherited from your parents
  • Random defects in the cell reproduction process

Different types of skin cancer behave in different ways. The most common types of skin cancer are generally minor. They cause small tumors on your skin that are easy to cure and unlikely to spread to other parts of your body. Others types, such as melanoma, are far more serious. If left untreated, melanoma can spread to distant organs and may become life-threatening.

Skin cancer is the most common form cancer in the world.

The Big Three

There are three common types of skin cancer: basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. Each type of skin cancer is named for the type of cells where the cancer begins. Several other types of skin cancer exist, but are extremely rare.


Skin cancer incidence by type

Basal cell carcinomas, named for the cells in the bottom layer of the epidermis, are the most common type of skin cancer tumors and are the least dangerous of the three.

Squamous cell carcinomas, named for the cells that are in the middle layer of your skin, are less common but more dangerous—if left untreated, squamous cell carcinomas may cause significant disfiguration. While squamous cell carcinomas are capable of spreading to other parts of your body, they are rarely fatal when treated promptly.

Melanoma, named for the melanocyte cells that create the pigment that gives skin its color, is the rarest of the three main types of skin cancer, but is the most likely to spread to other parts of your body. Melanoma is the most dangerous type of skin cancer and can be fatal.

What causes skin cancer?

Scientists believe that exposure to ultraviolet (UV) radiation is the cause of more than 90% of skin cancer cases. UV radiation is another name for the light and heat created by the sun or indoor tanning lamps.

Exposure to the sun or tanning lamps increases the risk of all types of skin cancer. People who experience prolonged exposure to UV radiation during childhood, particularly if they experience severe sun burns, are more likely to develop melanomas and basal cell carcinomas later in life. People with lighter colored skin, hair, and eyes are also at higher risk of developing skin cancer.

Scientists estimate that more than 8,000 people are diagnosed with skin cancer every day in the U.S.

Skin Cancer Risk Factors

Some people are more likely to develop skin cancer than others. By collecting and studying data about the genetic characteristics, environmental influences, and lifestyle choices of skin cancer patients over many years, doctors have identified certain factors that are common among people who have developed the disease. While some of these factors have not been proven to cause skin cancer, each has been observed as being common among a significant number of people with skin cancer.

 One in five Americans will develop some form of skin cancer in their lifetime.

Primary genetic risk factors:

  • Fairer or lighter skin color
  • A family history of skin cancer
  • Skin that burns or becomes painful in the sun
  • Skin that reddens or becomes freckled in the sun
  • Eyes that are blue or green
  • Hair that is blond or red
  • The presence of 50 or more common moles

Primary environmental risk factors:

  • A history of sunburns, especially during childhood or adolescence
  • At least one instance of severe blistering
  • Excessive sun exposure, even if skin does not blister
  • Tanning, either indoor or outdoor
  • Living at high altitude climates
  • Living in warm, sunny climates
  • Exposure to certain chemicals, such as coal tar, arsenic, and paraffin.
  • A weakened immune system