Abstract: Abstract Objective：To investigate the effects of transfected XPD gene on the growth of hepatoma cell SMMC-7721 and the expression of ERG gene. Methods: The XPD gene was transfected into SMMC-7721 with Lipofectamine 2000. There were four groups in this study including SMMC-7721 - pEGFP- N2-XPD group（XPD group), SMMC-7721-pEGFP-N2 group (N2 group), Lipofectamine group (Lip group ) and blank control group. Reverse transcriptase PCR and Western blot were used to measure the expressions of XPD and ERG at mRNA and protein levels,respectively.The cell prolifera tion was assessed by MTT assay and the cell apoptosis was examined by flow cytometry . Results: Compared with N2 group, Lip group and blank control group, the expression of EGR mRNA and protein decreased significantly in XPD group (P < 0.01), in contranst the expression of XPD mRNA and protein were enhanced obviously in XPD group (P < 0.01). The proliferation of SMMC-7721 cells was markedly inhibited and the apoptosis of SMMC-7721 cells was increased obviously after transfection of XPD(P < 0.01). Conclusion: The wild-type XPD could inhibit the expression of ERG ，decrease the proliferation of SMMC-7721 cells and enhanced the apoptosis of SMMC-7721 cells in vitro.

Key words: liver neoplasms, transfection, XPD gene, ERG gene, p53 gene, proliferation, apoptosis