Abstract: Objective To study the expression of MAGEA9 gene in hepatocellular carcinoma (HCC) and the effect of silencing of MAGEA9 gene on the cell growth of Focus and PLC/PRF/5 this derived from liver cancer. Methods Semi-quantitative RT-PCR was performed to detect the expression of MAGEA9 in 48 pairs of HCCs compared with adjacent non-cancerous livers (non-HCC). We also evaluated the expression of MAGEA9 gene in 14 normal human tissues and 17 HCC-derived cell lines by RT-PCR. The cell growth curve was observed after silencing of MAGEA9 by siRNAs using CCK-8 reagent. Finally, we constructed the shRNA expression vector pSUPER-shRNA-M9 for colony formation assay. Results MAGEA9 was significantly up-regulated in 29% (14/48) HCC specimens at mRNA level compared with non-HCCs. MAGEA9 gene was specifically expressed in testis, heart, spleen and kidney. Interestingly, silencing of MAGEA9 gene in Focus and PLC/PRF/5 cells markedly inhibited cell growth with siRNA-M9 as compared with the control cells transfected by siRNA-NC. In addition, the colony formation efficiency was depressed by shRNA-M9. Conclusion The expression of MAGEA9 gene may be important for the malignant growth of hepatocarcinoma cells. Moreover, it may play an important role in the hepatocarcinogenesis. In further study, it may be used as a new marker or a potential therapeutic target for HCC.