An isolated antibody, comprising heavy chain complementary determining regions CDR1, CDR2, and CDR3 from a heavy chain variable region sequence having SEQ ID NO: 1 or 3; light chain complementary determining regions CDR1, CDR2, and CDR3 from a light chain variable region sequence having SEQ ID NO: 2 or 4; wherein the antibody binds specifically to both vascular endothelial growth factor receptor-2 (VEGFR2) and vascular endothelial growth factor receptor-3 (VEGFR3).