EPAS1 and glioblastoma: In our previous studies, the expression of phosphorylated extracellular signal-regulated kinases 1/2 (pERK1/2), phosphorylated c-Jun NH2-terminal kinases (pJNK), other stem cell markers (such as Nestin, CD133, and NG2 proteoglycan), as well as angiogenesis-related factors (CD105, VEGF, VEGFR1/2, HIF-1α, and HIF-2α), has been demonstrated in GBM and PT tissue, even in the absence of frankly neoplastic cells [7,8,9,11,46,47].