Compared with the adjacent nonneoplastic tissues, the expression levels of GRB2 (IRS for HCC vs. nonneoplastic liver: 6.32±1.50 vs. 2.67±0.32, P<0.001, Figure 5C) and GAB1 (IRS for HCC vs. nonneoplastic liver: 5.72±0.95 vs. 1.75±0.48, P<0.001, Figure 5F) proteins were all significantly increased in HCC tissues. This evidence concerns the gene GAB1 and hepatocellular carcinoma.