The sun--friend or foe?
D002280:Basal Cell Carcinoma / Q000209:etiology*; D002294:Carcinoma, Squamous Cell / Q000209:etiology*; D006801:Humans; D009381:Neoplasms, Radiation-Induced / Q000209:etiology*; D011230:Precancerous Conditions / Q000209:etiology; D012878:Skin Neoplasms / Q000209:etiology*; D013472:Sunlight / Q000009:adverse effects*