Causes of Skin Cancer

By far, the most profound of the causes of skin cancer is exposure to ultraviolet (UV) radiation from the sun. As with other forms of cancer, skin cancer occurs when genetic damage occurs in cells (mutations) which causes the cells to begin growing in a disordered, uncontrollable pattern. While other factors can contribute to this damage in skin cells, the most common factor is exposure to UV radiation from sunlight.

Sunlight is a form of radiation. It contains radiation of various energies. Some of the lower energy radiation from the sun is harmless, such as the visible light that allows us to see. However, higher energy radiation can cause damage to cells, including mutations which can lead to cancer. UV radiation exists in two forms, UVA (ultraviolet A) and UVB (ultraviolet B). Both are probably causes of skin cancer. Besides being causes of skin cancer, these UV rays also cause sunburn and sun tan and lead to other damage that makes the skin wrinkled and prematurely old.

While all types of skin cancer are caused by exposure to UV radiation, they are somewhat different. For example, squamous cell carcinoma and basal cell carcinoma are probably associated with the overall prolonged exposure to sunlight. Therefore, they most commonly occur in areas of the body that get the most sun exposure throughout your lifetime, your head, face, neck, hands and arms. On the other hand, malignant melanoma appears to be more associated with brief, intense sun exposure as what happens with sunbathing. Therefore, these tumors can arise anywhere on the skin but often arise from skin that is not always exposured except when sunbathing, such as the legs, back, buttock, etc.

Risk Factors for Skin Cancer

• Sun Exposure: As already discussed, total sun exposure is associated with one's risk for developing skin cancer due to exposure to UV radiation in the sunlight. The more exposure, the higher your risk. Sun screen lotions that block both UVA and UVB radiation do help to decrease your sun exposure and therefore your risk for skin cancer.
• Tanning Booths/Beds: Yes, tanning in a tanning bed does cause cancer! The tanning lamps do emit UV radiation, which is why they cause you to tan. Therefore, using a tanning booth is not better for you than sunlight itself. These do contribute to your total exposure to UV light.
• Fair Skin: People with more pigment in their skin (darker skin) are more protected from the harmful effects of UV rays. Therefore, people with more fair skin, such as individuals of northern European decent, are at increased risk for skin cancer.
• Socioeconomic Status: As mentioned above, melanoma appears to be most associated with brief, intense sun exposures such as occurs with sunbathing. This is more common in people with higher socioeconomic status who often take vacations to areas near the equator (where sun exposure is the most intense and direct) and sit out for several days in the sun.
• Age: The longer we live, the more cumulative exposure to sunlight our skin gets. Also, mutations occur from other causes as we age, including from other toxins in our diet and environment. Therefore, skin cancer occurs more frequently in older individuals.
• Family History and Genetics: Besides skin color, our genetics often affect our susceptibility to various types of cancer. Some families and genetics are more prone to causes of skin cancer and some familial syndromes are associated with very high rates of skin cancer.
• Radiation exposure: Other forms of radiation exposure other than sunlight can also increase the risk for skin cancer.
• Other Carcinogens: Other carcinogens we are exposed to in our diet or the environment around us can contribute to skin cancer. Some chemicals that are known to be associated with an increased risk for skin cancer include coal tar, soot, pitch, asphalt, creosote, arsenic and some petroleum products. Some viruses have been suggested as one of the causes of skin cancer, such as human papilloma virus, which also causes warts.