Question: what is the greatest risk factor for skin cancer?
Answer: Ultraviolet (UV) light exposure. Exposure to ultraviolet (UV) rays is thought to be the major risk factor for most skin cancers. ... 
Having light-colored skin. ... 
Being older. ... 
Being male. ... 
Exposure to certain chemicals. ... 
Radiation exposure. ... 
Previous skin cancer. ... 
Long-term or severe skin inflammation or injury.