HIF1A and central nervous system cancer: In this mechanism, signals, such as vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and hypoxia-inducible factor 1-alpha (HIF-1α), are released from glioma stem cells in low oxygen states [9], causing proteases to detach pericytes from existing vessels and forming a weak extracellular matrix around the vessel wall that promotes endothelial cell remodeling [10].