Cell apoptotic rate detected by flow cytometry. (A) The cell apoptotic rate of HepG2, HepG2/pcDNA3.1, HepG2/ADM and HepG2/ABCG2 cells was detected by flow cytometry. (B) The flow cytometry results indicated that there was no significant difference between the apoptotic rate of HepG2/ADM, HepG2/ABCG2, HepG2/pcDNA3.1 cells and their parental HepG2 cells. Values are expressed as the mean +/- standard deviation (n=3). ADM, Adriamycin; ABCG2, adenosine triphosphate-binding cassette transporter G2.