Mechanisms of drug resistance to vascular endothelial growth factor (VEGF) inhibitors.

: Angiogenesis inhibitors have a major role in the treatment of varying cancers today. While originally thought to be independent of resistance, increasing data suggests varying mechanisms that bring about drug resistance, either intrinsically or through adaptation. The role of vascular endothelial growth factor single nucleotide polymorphisms (VEGF SNPs) in terms of therapeutic response and toxicity has increasingly been recognized, as well as its potential for contributing to drug resistance. This review will focus on theories, preclinical models, and clinical trials that help elucidate the mechanisms of resistance and clinical response to angiogenesis inhibitors.