Recent studies suggested a dark side of Nrf2 pathway by showing that high level of Nrf2 can promote cancer formation and contribute to chemoresistance (Hayes and McMahon, 2006; Lau et al., 2008; Wang et al., 2008; Kensler and Wakabayashi, 2010; Gañán-Gómez et al., 2013). This evidence concerns the gene NFE2L2 and cancer.