HGF and neoplasm: Both BMSCs and MM plasma cells can secrete vascular endothelial growth factor (VEGF), IGF-1, interleukin 1 (IL-1), transforming growth factor beta (TGF-β), angiopoietin-1 (Ang-1), platelet derived growth factor (PDGF), basic-fibroblast growth factor (bFGF), and hepatocyte growth factor (HGF) which have been shown to promote osteoclastogenesis, tumor growth, and angiogenesis in MM (39).