KDR and glioblastoma: Cotreatment with AKB-9778 significantly attenuated the 4E2-driven suppression of VEGFR2 phosphorylation but showed no additional effect on 4E2-induced Tie2 phosphorylation in GBM vessels (Fig. 8e, f), verifying that 4E2 can promote VE-PTP-mediated VEGFR2 dephosphorylation in the context of GBM.