HGF and neoplasm: TAMs can express cytokines that stimulate tumor cell proliferation and survival by regulating the transforming growth factor (TGF-β), the epithelial growth factor (EGF) as well as the EGF ligants and receptor (EGFR), the hepatocyte growth factor (HGF), the platelet-derived growth factor (PDGF), and the fibroblast growth factor (FGF) [48].