Sun protection of human skin: from A to Z

Solar radiation contains about 6.8% ultraviolet (UV) radiation. UV radiation is still regarded as one of the most important risk factors for both nonmelanoma skin cancer (NMSC; predominantly basal cell carcinoma and squamous cell carcinoma) and malignant melanoma (MM). To avoid induction and persistence of UV-induced mutations, our skin is armed with an arsenal of endogenous protective mechanisms such as induction of cell cycle arrest, repair mechanisms, immunosurveillance and the initiation of various types of cell death. Exogenous sun protection includes a range of behaviors such as avoiding extensive sun exposure, wearing UV-proof clothing and appropriate application of topical sunscreens.