Synthetic antioxidants and extracts of cruciferous vegetables, including broccoli, are potent inducers of NQO1 homozygosity for the T/T genotype of NQO1: (NQO1*2, rs1800566 T) strongly predicted the decision to investigate the role of the 609C-to-T polymorphism in leukemia in general. Overlapping human NMOR1 cDNAs identified the 3 mRNA species in locus 16q22.1; NQO1. cDNA encodes a dioxin-inducible cytosolic form of human NAD(P)H:quinone, NQO1 is a 2-electron reductase that detoxifies quinones derived from the oxidation of phenolic metabolites of benzene. The NQO2 gene revealed presence of three copies of xenobiotic response element (XRE). NQO2 gene is has seven exons interrupted by six introns as compared to the cloned NQO1 gene which contains six exons. These elements regulate tissue specific expression and induction of the NQO2 gene in response to xenobiotics and antioxidants response element (ARE). Inhibition of QR2 by melatonin may explain melatonin's protective effect which opens new pharmacological perspectives for GPR50 despite the lack of endogenous or synthetic ligands. This orphan receptor also named GPR50 does not bind melatonin The third melatonin binding site, MT3 is a non-classical one: NQO2. At least two types of quinone reductases are present in plants are two non-covalent that can start multiple cross products invasive (e. coli) into the NQO1, and equivalent to some, the equivalent third position nucleotides are always either two purines (A/G) or two pyrimidines (C/T) thymine (T) and cytosine (C).