EGFR and hepatocellular carcinoma: Although both TGFα and EGF are high-affinity ligands of EGFR [75], elevated secretion of TGFα was observed in 65% of HCC patients, whereas only 16% of HCC patients showed increased EGF secretion [76], suggesting that TGFα may play a major role in EGFR signaling activation in HCC.