E2F1 and hepatocellular carcinoma: IHC staining further showed that compared to sh-NC + OE-NC group, Ki67 expressed a weaken intensity in HCC tissues with E2F1 downregulation, indicating that E2F1 depletion could inhibit HCC cell proliferation, whereas this effect was abolished by KDM4A-AS1 overexpression (Fig. 7D).