Any monoclonal antibody directed against the human tyrosine kinase vascular endothelial growth factor receptor (VEGFR), with potential anti-angiogenic and antineoplastic activities. An anti-VEGFR monoclonal antibody binds to and inhibits the activity of VEGFR, which may prevent the activation of downstream signaling pathways and tumor angiogenesis; the subsequent reduction in tumor nutrient supply may inhibit tumor cell proliferation. The expression of the pro-angiogenic growth factor VEGF is associated with tumor angiogenesis and tumor cell proliferation and invasion. [ ]