Most skin cancer is caused by ultraviolet (UV) light damaging the DNA in skin cells. The main source of UV light is sunlight.
Sunlight contains three types of UV light:
- ultraviolet A (UVA)
- ultraviolet B (UVB)
- ultraviolet C (UVC)
UVC is filtered out by the earth's atmosphere. UVA and UVB damage skin over time, making it more likely for skin cancers to develop. UVB is thought to be the main cause of non-melanoma skin cancer.
Artificial sources of UV light, such as sunlamps and tanning beds, also increase your risk of developing skin cancer.
Repeated sunburn, either by the sun or artificial sources of light, will make your skin more vulnerable to non-melanoma skin cancer.
In most cases, non-melanoma skin cancer does not run in families. However, research has shown that some families have a higher than average number of members who develop the condition.
For example, if you have a parent who's had squamous cell carcinoma (SCC), your risk of also getting SCC is 2 to 3 times higher than average.
Having a family history of melanoma also increases your risk of getting basal cell carcinoma.
Other risk factors
Certain factors are thought to increase your chances of developing all types of skin cancer.
- having pale skin that does not tan easily
- have blonde or red hair
- having blue eyes
- older age
- having a large number of moles
- having a large number of freckles
- having an area of skin previously damaged by burning or radiotherapy treatment
- having a condition that suppresses your immune system, such as HIV
- taking medicines that suppress your immune system (immunosuppressants), commonly used after organ transplants
- exposure to certain chemicals, such as creosote and arsenic
- having been previously diagnosed with skin cancer
The Cancer Research UK website has more information about skin cancer risks and causes.