CXCR4 and glioblastoma: GBM cell proliferation, VEGF synthesis, and endothelial tube formation are all stimulated by CXCR4 generated from GBM EVs, and the C-X-C Motif Chemokine Ligand 12 (CXCL12) ligand enables reciprocal communication between GBM and endothelial cells [31, 41].