Nrf2 is a transcription factor responsible for cellular defense against the cytotoxic effect of oxidative stress.  Under normal condition, Nrf 2 is kept in cytoplasm by Keap1 protein, which leads to Nrf2 degradation, and the half-life of Nrf2 is about 20 minutes. Oxidative stress results in dissociation of Nrf2 from Keap, and then Nrf2 translocates to the nucleus, where it binds to the specific DNA sequence - the antioxidant response element (ARE) in the promoters of its target genes, including Heme oxygenase (HO-1) and glutathione S-transferase (GST).  Because of its importance in regulating oxidative stress, Nrf2 is believed to be a good drug target candidate in the prevention and treatment of cancers.