Inhibition of angiogenesis with antibodies against vascular endothelial growth factor (VEGF) and VEGF receptor antagonists has become an established treatment for cancer. An unanticipated side effect of angiogenesis inhibitors is the development of hypertension. The pathogenesis of this hypertension is unknown. Not all patients will develop hypertension. However, it is not known which patient will and which patient will not develop hypertension.