Skin cancer develops, as do other types of cancer, because of damage or changes to cell DNA. When DNA is damaged, the orderly process of new cells replacing old cells goes haywire. Old cells don't die off as they should, and new cells are made when they are not needed. These excess abnormal cells can form a mass, called a tumor.
Ultraviolet (UV) radiation is the major cause of damage to skin cells that leads to skin cancer. But when it comes to cancer, experts talk about risk factors, not causes. Risk factors are things that increase your risk of getting a disease. The link between UV radiation and skin cancer is strong. Yet some people with high UV exposure don't get cancer, and some people with little UV exposure do. And skin cancer, especially melanoma, sometimes occurs on skin that is rarely exposed to the sun.
Still, UV radiation is the top risk factor for skin cancer, and people with high levels of UV exposure have the greatest risk.
The main source of UV radiation is sunlight, but it is also produced by artificial sources such as tanning booths. A person can get a high level of UV radiation from:
- Living in an area that has bright sunlight year-round
- Living at a high altitude
- Spending a lot of time outdoors
- Using a sunlamp or tanning bed
Taking steps to limit UV exposure is important for everyone, but it may be even more important if you have any additional risk factors. These include having:
- Light skin that freckles or burns easily (often with light-colored hair and eyes)
- Lots of moles or irregularly shaped moles
- A personal history of skin cancer
- A family history of skin cancer
- Scars, burns, or long-term or severe skin inflammation
- Past treatment with radiation therapy
- A condition or a medication you take that lowers your immune system
- A precancerous skin condition, such as actinic keratosis or Bowen's disease
- A rare genetic condition, such as xeroderma pigmentosum, basal cell nevus syndrome, or albinism.
Created on 11/05/1999
Updated on 06/20/2011
- American Cancer Society. Melanoma skin cancer.
- American Society of Clinical Oncology. Skin cancer (non-melanoma): risk factors and prevention.
- American Cancer Society. Skin cancer prevention and early detection.
- National Cancer Institute. What you need to know about melanoma and other skin cancers.