POR and cancer: Indeed, cytochrome P450 oxidoreductase (POR) combines with two cofactors (flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD)) to directly supply electrons to the P450 enzyme from nicotinamide adenine dinucleotide phosphate (NADPH, an essential electron donor in all organisms), thereby promoting PUFA peroxidation in cancer cells in an ALOX-independent manner65 (Fig. 2).