HIF1A and glioblastoma: ,150 Moreover, GBM cells promote the selective migration of NSCs into primary GBMs and track invasive lesions throughout the brain by releasing soluble factors such as CXCL12, hypoxia-inducible factor-1 alpha (HIF-1α), platelet-derived growth factor (PDGF), and VEGF.151, 152, 153, 154