Abstract: Objective To investigate the expression of ATP-dependent Clp protease ATP-binding subunit（ClpX） in hepatocellular carcinoma（HCC）and its clinical significance. Methods The HCC tissues and corresponding adjacent normal tissues of 166 patients with HCC who underwent radical hepatectomy at the Department of Hepatobiliary Surgery，Xijing Hospital of Air Force Military Medical University from January 2013 to December 2014 were collected. The expression of ClpX in HCC tissues and corresponding adjacent normal tissues was detected by Immunohistochemical staining，and the relationship between the expression of ClpX protein and the clinicopathological characteristics and prognosis of HCC patients was analyzed. After interfered and overexpressed with ClpX，respectively，in HCC cell line SNU739，the cell proliferation was detected by MTS assay. Results The expression of ClpX in HCC tissues was significantly lower than that in adjacent normal tissues（P<0.001），and the overall survival of HCC patients with high ClpX expression was significantly better than that of patients with low ClpX expression （P=0.009）. The expression of ClpX was negatively related to TNM stage （P=0.008），and low ClpX expression was an independent risk factor affecting the overall survival of HCC patients （P=0.046）. After interfered with the ClpX expression，the proliferation ability of SNU739 cells was significantly higher than that of the control group （P<0.001），while the proliferation ability of SNU739 cells decreased significantly after overexpression of ClpX（P<0.001）. Conclusions ClpX is lowly expressed in HCC tissues，the patient with low expression of ClpX has a poorer prognosis，and down-regulation of ClpX can promote cell proliferation. ClpX may serve as a potential prognostic marker for patients with HCC.

Key words: Hepatocellular carcinoma, ClpX, Clinicopathology, Prognosis, Proliferation