PARP1 and hepatocellular carcinoma: In the present study, in order to clarify the impact of PARP-1 in cell growth and cell cycle progression, we investigated the effects of pharmacologic PARP-1 inhibitors 3-aminobenzamide (3AB) and N-(6-oxo-5, 6-dihydrophenanthridin-2-yl)-2-(N, N-dimethylamino)acetami (PJ34), enzymatic PARP-1 activator H2O2, PARP-1 siRNA, as well as PARP-1 expressing plasmid on proliferation and cell cycle distribution of human hepatoma cells.