['To investigate the effect of overexpression of bcl-2 on ethanol-induced apoptosis of primary hepatocellular carcinoma (HCC) cells.', 'The retrovirus expression vector pDOR-SB containing human bcl-2 cDNA was introduced into a human HCC cell line HCC-9204 by liposome-mediated transfection. pDOR-transfected and non-transfected HCC-9204 cells were used as controls. The expression of Bcl-2 protein by transfected HCC-9204 cells was detected by the immunohistochemical method. Then the cells were cloned with the limited dilution method continually until a monoclonal cell strain whose positive rate of Bcl-2 protein was 100% detected by flow cytometry was obtained. The killing rates of cells were detected by Methabenzthiazuron assay after the treatment of 6% ethanol for 6 h. The extent of apoptosis was analyzed by transferase-mediated dUTP nick end labeling (TUNEL) staining and flow cytometry.', 'Most of the pDOR-SB-transfected cells demonstrated Bcl-2 positive signals, while no signal was found in the controls. The positive rate of Bcl-2 protein detected by flow cytometry in the obtained monoclonal cell strain, which was named HCC-bcl2, was 100% after the cells had been cloned 3 times continually. The killing rate, TUNEL index and the scale of sub-G1 apoptotic peak in HCC-bcl2 cells were all significantly lower than those in the control cells.'] Does overexpression of bcl-2 protect hepatoma cell line HCC-9204 from ethanol-induced apoptosis?