〔Abstract〕 Abstract Objective To explore the expression level of PPFIA4 in hepatocellular carcinoma tissues and HCCLM3 cells and its regulation of the biological behavior of hepatocellular carcinoma. Methods Bioinformatics analysis , Western blot , and immunohistochemistry were employed to detect the expression of PPFIA4 in tumor tissues of pa- tients with hepatocellular carcinoma and analyze the prognosis of these patients . An siRNA plasmid was designed to knock down the expression of PPFIA4 in HCCLM3 cells . The effects of PPFIA4 knockdown on the migration and invasion abilities of HCCLM3 cells were then evaluated using scratch healing and Transwell assays . Furthermore , Western blot was utilized to detect the expression levels of epithelial-mesenchymal transition (EMT)-related protein markers in the HCCLM3 cell line after transfection with the siRNA plasmid . Results PPFIA4 was highly expressed in hepatocellular carcinoma tissues and hepatocellular carcinoma cells ( HCCLM3 , Li-7 , MHCC97H ) ; the high expression of PPFIA4 indicated that the clinical stage of patients was late and the overall survival (OS) was short. After knocking down the expression of PPFIA4 in HCCLM3 cell line , the migration and invasion ability of HCCLM3 cells decreased (P < 0. 001) and the expression of EMT markers changed . The expression of epithelial cell marker E-cadherin increased ( P < 0. 01) , while the expression of mesenchymal markers Vimentin and N-cadherin de- creased(P < 0. 05 , P < 0. 01) . Conclusion PPFIA4 is highly expressed in hepatocellular carcinoma tissues and hepatocellular carcinoma cell lines and is associated with poor prognosis of patients . Silencing PPFIA4 can regulate the biological behavior of hepatocellular carcinoma cells and inhibit the migration and invasion of HCCLM3 cells . The specific mechanism may be related to EMT.