Interestingly, interruption of VEGF signaling may not primarily act through impaired angiogenesis to mediate effects of these drugs on tumorigenesis, but may also “normalize” leaky tumor vasculature to allow more efficient delivery of additional chemotherapeutic drugs and by altering endothelial progenitor cell homing and function in the vasculature [36, 37]. This evidence concerns the gene VEGFA and neoplasm.