Abstract
Glioblastomas are among the most vascular tumors due to the expression of a variety of proangiogenic factors. New drug regimens are being developed to target angiogenesis in an attempt to arrest tumor growth. In particular, the vascular endothelial growth factor (VEGF) pathway has been a prime drug target. Preliminary results with anti-VEGF agents have been promising with prolonged progression-free survival reported. In addition, the antipermeability effects of anti-VEGF agents have important consequences for tumor imaging and for patient quality of life by decreasing corticosteroid dependence. Unfortunately, the response to anti-VEGF therapy is transient, and the majority of patients eventually relapsed, so more work is needed to understand the mechanisms of tumor escape.