HGF and neoplasm: During tumor development, GAMs continuously exert their significant protumorigenic functions through various cytokines, including transforming growth factor-beta (TGF-β), epidermal growth factor (EGF), platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), IL-1β, IL-6, IL-10, and matrix metallopeptidase-2 (MMP-2) (Figure 2).