FLT1 and neoplasm: Bevacizumab is a recombinant humanized monoclonal antibody that can selectively bind to human vascular endothelial growth factor (VEGF) and block its biological activity, and inhibit the binding of VEGF to its receptors Flt-1 and KDR on endothelial cells, thus reducing tumor angiogenesis and suppressing tumor growth (9).