STAT3 and hepatocellular carcinoma: As shown in Fig. 7E, treatment using rapamycin effectively inhibited the activity of mTOR and S6, and inhibition of mTOR suppressed STAT3 phosphorylation and ID1 expression in both HCC cell lines, suggesting that STAT3/ID1 axis was controlled by the AKT/mTOR signaling pathway in both HCC cell lines.