Resistance to anti-angiogenic agents: a brief review of mechanisms and consequences

A capacity for neoangiogenesis is a fundamental property of cancer (1,2). With the clinical application of multiple inhibitors of vascular endothelial growth factor (VEGF) signaling, angiogenesis is a validated therapeutic target in several malignancies including renal cell, colon and lung cancer. However, the overall clinical benefit of agents targeting VEGF has been less than what was hoped. This lack of benefit appears to be substantially due to primary or acquired resistance to these drugs (3).