Studies showed that As2O3 synergized with sorafenib to down-regulate the expression on of cyclin D1, resulting in cell arrested at G0/G1 in HCC cells [23], and our results may suggest that As2O3 re-sensitized hpyoxia chemo-resistance via down-regulation of cyclin D1, which results in cell cycle arrest at G0/G1 in HBx-HepG2 cells. This evidence concerns the gene CCND1 and hepatocellular carcinoma.