A humanized immunoglobulin (Ig) G2 monoclonal antibody directed against the human hepatocyte growth factor receptor (HGFR or c-Met), with potential antineoplastic activity. Upon administration, anti-c-Met monoclonal antibody HLX55 specifically binds to the semaphorin (Sema)/Plexins-Semaphorins-Integrins (PSI) domain of c-Met, which prevents the binding of c-Met to its ligand HGF and the subsequent activation of the HGF/c-Met signaling pathway. In addition, HLX55 promotes c-Met degradation, which further inhibits c-Met-mediated signaling. This may result in cell death in c-Met-expressing tumor cells. c-Met, a receptor tyrosine kinase overexpressed or mutated in many tumor cell types, plays a key role in cancer cell growth, survival, angiogenesis, invasion, and metastasis.