What causes basal cell carcinoma?

The cause of basal cell carcinoma is not known. There could be different causes in different people. However, risk factors include:

• Exposure to ultraviolet radiation – For example, risk rises after a high number of sunburns or radiation therapy, as given certain cancers. These effects are particularly important if exposure occurs in childhood or early adulthood.

• Hair, eye and skin color (higher risk with fair skin, light-colored eyes, red hair)

• Advancing age

• Certain genetic conditions, such as xeroderma pigmentosum

• Immunosuppression, as with HIV infection or organ transplantation

A leading theory about the cause of most basal cell carcinomas is that they are due to a combination of skin damage by radiation and genetic factors.