Abstract: Objective To investigate the expression of pescadillo ribosomal biogenesis factor 1（PES1） in hepatocellular carcinoma （HCC）and its effect on the growth of hepatocellular BEL-7402 cells. Methods The expression of PES1 in HCC and adjacent normal tissues was detected by immunohistochemical （IHC）staining. The protein expression of PES1，CDK4 and CDC25A were detected by Western blot after BEL-7402 cells were transfected with PES1 siRNA，and the cell growth was detected by MTS，the cells cycle and apoptosis were detected by flow cytometry. Results The positive expression rate of PES1 in 95 HCC tissues was higher than that of the adjacent normal tissues（90.5% vs 72.6%，χ²=10.122，P=0.001），and the IHC staining score of PES1 in HCC tissues was higher than that of the adjacent normal tissues（6.30±3.56 vs 2.10±1.64，t=10.423，P<0.001）. The expression of PES1 was related to tumor size，portal vein tumor thrombus and TNM stage in HCC patients（all P<0.05）. The overall survival of HCC patients with high expression of PES1 were shorter than those with PES1 low expression（P<0.05）. Compared with the control group，the growth of cells in the PES1 small interfering RNA group was inhibited（P<0.01），the proportion of cells in G1 phase increased，and the proportion of cells in S phase decreased （all P<0.05）. The expression of CDK4 and CDC25A protein was down-regulated，but the cells showed no obvious change in apoptosis. Conclusions The expression of PES1 in HCC tissues is up-regulated and relate to the prognosis of HCC patients. PES1 may accelerate the G1/S phase transformation and promote the cells growth by up-regulating the expression of CDK4 and CDC25A.

Key words: Hepatocellular carcinoma, PES1, Prognosis, Cells growth