HGF and hepatocellular carcinoma: The key signal transduction pathways in the pathogenesis of hepatocellular carcinoma include: VEGF, EGFR, Ras/Raf/Mek/Erk, phosphoinositide 3-kinase/Akt, mTOR, HGF/c-Met, Wnt, and Hedgehog signaling cascades40.