CXCL12 and glioblastoma: GBM cells with high expression or activation levels of bradykinin receptor‐2 (B2R),35 CXC receptor‐4 (CXCR4, the receptor of SDF‐1),36, 40 epidermal growth factor receptor (EGFR) variant III,41 inositol‐requiring enzyme (IRE)‐1α42 and ephrin‐B239 have been shown to have high vessel co‐option activity.