GBC cells were cultured with different concentrations of As2O3,the proliferative activity of the cells was detected by MTT methods,and the cell cycle status was carried out by flow cytometry(FCM).Western blot and RT-PCR were performed to analyse the expression of cyclin D1,D2,D3,CDK4 and CDK6.GBC cells were transient transfected with cyclin D1 promoter construct pGL3 and then treated by different doses of As2O3.The luciferase activity was measured.