HGF and neoplasm: On a cellular level, integrin β1 signaling is necessary for TGF-β mediated p38-signaling and EMT in mammary epithelial cells (Bhowmick et al., 2001), and in basal carcinoma, αvβ6-mediated TGF-β activation in epithelial cells leads to fibroblast-myofibroblasts transition and secretion of HGF by myofibroblasts; HGF in turn promotes invasiveness of tumor cell (Marsh et al., 2008).