HMOX1 and cancer: The Nrf2 target genes, such as heme oxygenase-1 (HO-1) and NAD(P)H-quinone oxidoreductase-1 (NQO1) are reported to mediate chemotherapy resistance in several cancers, including gastric (Yang et al., 2011) and colon cancers (Schlager and Powis, 1990).