EPAS1 and neoplasm: While HIF-1α is known to promote cell arrest via mTORC1 repression and other mechanisms (Brugarolas et al., 2004; Cam et al., 2010; Carmeliet et al., 1998; Goda et al., 2003; Koshiji et al., 2004), HIF-2α can activate mTORC1 to induce cell proliferation and growth in a number of cell types and organs, for example, tumour cells or the lung epithelium (Brusselmans et al., 2003; Cowburn et al., 2016; Elorza et al., 2012; Gordan et al., 2007; Hubbi and Semenza, 2015; Kondo et al., 2003; Raval et al., 2005; Torres-Capelli et al., 2016).