FLT1 and neoplasm: As a synthetic recombinant humanized immunoglobulin G1 monoclonal antibody, bevacizumab can specifically bind to VEGF and form an inhibitory combination of VEGF and endothelial cell surface receptors fms-related tyrosine kinase 1 and kinase insert domain receptor, thereby preventing endothelial cell proliferation and tumor angiogenesis and subsequently inhibiting tumor growth (22–24).