CXCR1 and glioblastoma: Highly malignant human glioblastoma cells (GBM) express a classical chemoattractant GPCR, FPR1, which recognizes a ligand, Annexin A1, released by necrotic GBM cells that mediates the proliferation of live GBM cells to increase their invasiveness and the production of angiogenic factors vascular endothelial growth factor (VEGF) and CXCL8 (IL-8), which stimulate VEGF receptor (VEGFR) and CXCR1/CXCR2 on vascular ECs to promote their migration and formation of new vasculature [316, 317].