Active Hif is a heterodimer, composed of an α subunit (Hif1α or Hif2α) and a β subunit (Hif1β, also called ARNT), and can bind hypoxia-responsive element (HRE), which is a very important mechanism in intestinal iron absorption (Mastrogiannaki et al., 2009; Shah et al., 2009) and under other conditions, such as cancer (Keith et al., 2011) and ischemia (Kapitsinou et al., 2014; Barteczek et al., 2017). Here, ARNT is linked to cancer.