HGF and cancer: Tumor hypoxia and tumor-associated proteins, such as hepatocyte growth factor (HGF), transforming growth factor β (TGF-β), platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), and epidermal growth factor (EGF), appear to be responsible for the induction or functional activation of EMT in cancer cells [8,11,12,13,14].