HGF and plasma cell myeloma: Elevated tumor and plasma HGF levels are also observed in patients with certain types of cancer such as invasive breast carcinoma, glioma, multiple myeloma and sarcomas.12, 13, 14, 15 Several in vivo studies have shown that activation of the HGF–cMET signaling pathway triggers cancer invasion and metastasis.16, 17, 18, 19 Thus, multiple therapeutic agents that target the HGF–cMET pathway in various cancers are under development.