Squamous cell carcinoma of the skin occurs when the flat, thin squamous cells in the outer layer of your skin develop errors in their DNA. Ordinarily, new cells push older cells toward your skin's surface, and the older cells die and are sloughed off. DNA errors disrupt this orderly pattern, causing cells to grow out of control, with squamous cell carcinoma of the skin as the result.

Ultraviolet light and other potential causes

Much of the damage to DNA in skin cells results from ultraviolet (UV) radiation found in sunlight and in commercial tanning lamps and tanning beds.

But sun exposure doesn't explain skin cancers that develop on skin not ordinarily exposed to sunlight. This indicates that other factors may contribute to your risk of skin cancer, such as being exposed to toxic substances or having a condition that weakens your immune system.

Nov. 27, 2014

You Are ... The Campaign for Mayo Clinic

Mayo Clinic is a not-for-profit organization. Make a difference today.