Angiogenesis inhibitors increase tumor stem cells.

The clinical efficacy of angiogenesis inhibitors targeting the vascular endothelial growth factor pathway has recently been met with numerous phase III failures that showed modest survival benefits. Understanding the resistance mechanisms of antiangiogenic therapy is essential to overcoming the limited effectiveness of VEGF-pathway inhibitors. A recent study published in the Proceedings of the National Academy of Sciences provides a novel explanation to the treatment limitations of angiogenesis inhibitors and suggests a potential strategy to improve the clinical utility of these agents.