NFKB1 and neoplasm: The increase in oxidants, the preventive effect on cytotoxicity of antioxidants, the known role of free radicals in activating NF-κB (Schoonbroodt and Piette, 2000) and the prevention of the increase in cell death and Fas/Fas L expression by the prevention of NF-κB activation are in support of the implication of the rise in free radicals in the cytotoxic effect of melatonin in some particular types of tumours.