The HHEX gene is bound by POU5F1 (OCT4) (Boyer et al. 2005), SOX2 (Boyer et al. 2005), and NANOG (Boyer et al. 2005, Lister et al. 2009) and POU5F1 represses expression (Babaie et al. 2007, Kunarso et al. 2010). POU5F1, SOX2, and NANOG bind adjacently (Boyer et al. 2005) therefore POU5F1 and SOX2 may heterodimerize. As inferred from mouse, HHEX is required for hepatic differentiation (Hunter et al. 2007), hematopoiesis (Jayaraman et al. 2000), and endodermal tissues for forebrain and thyroid (Martinez Barbera et al. 2000).