In clinical samples, PEG3 expression was positively corelated with p-Erk1/2Thr202/Tyr204 and p-mTORSer2448, implying that PEG3 is involved in the Erk/mTOR signaling pathway and can be used as a special prognostic marker for HCC patients with hyperactive Erk and mTOR. This evidence concerns the gene MAPK3 and hepatocellular carcinoma.