E2F1 and hepatocellular carcinoma: Hepatoma cells treated with ISX or E2F1 shRNAi showed significant decreases in growth rate (69% and 43%, respectively, according to cell counts at 72 h cultivation; 44% and 25%, respectively, according to the BrdU incorporation assay) from those observed in cells with pEGFP controls (Figure 5A and 5B).