Ectopic expression of NRF2 can clear ROS by up-regulating antioxidant enzymes [for example, glutamate-cysteine ligase catalytic subunit (GCLC), heme oxygenase-1 and NADH quinone oxidoreductase 1] and help cancer cells escape death; by contrast, downregulating NRF2 expression in tumor cells can promote the killing induced by therapeutic drugs [20]. This evidence concerns the gene GCLC and cancer.