title: I've heard that sleeping with light in your bedroom--like a night light or a TV that's left on--can cause cancer.  Is this true?
mesh_terms: D006801:Humans; D008029:Lighting / Q000009:adverse effects*; D008550:Melatonin / Q000378:metabolism; D009369:Neoplasms / Q000209:etiology*
chemical_list: D008550:Melatonin