An article in Oncogene
further explains how ultraviolet (UV) radiation helps transform skin cells into basal cell carcinoma. Cells exposed to UV radiation ramp up production of protein kinase D, an enzyme that helps cells survive. The effect is cumulative: more exposure causes more protein kinase D expression, increasing the likelihood that DNA damaged skin cells survive and replicate. Pretreating skin cells with antioxidants reduced protein kinase D activation, suggesting that free radicals also contribute to skin cancer development.