Curcumin, a polyphenol is one such metabolite, which prevents cancer by Nrf2 signaling activation, modulation of inducible nitric oxide synthase (iNOS) and cyclo-oxygenase (COX2), restoring tumor suppressor p53, and inducing phase-2 antioxidant enzymes glutathione-S-transferase (GST), glutathione reductase (GR), and NQO1 (Das and Vinayak, 2015). This evidence concerns the gene NOS2 and cancer.