Objective To investigate the expression level of FEN1 in hepatocellular carcinoma (HCC) cells and its role in the progression of HCC.

Methods The expressions of FEN1 in 52 matched pairs of HCC tissues and corresponding normal tissues were measured by RT-qPCR and immunohistochemical staining. Specific FEN1 siRNA was transfected in HepG2 cells and the transfection efficiency was detected by Western blot. Moreover, cell proliferation was analyzed by MTT assay and cells apoptosis was determined by flow cytometry. Then, cell migration and invasion were detected by Transwell assays.

Results FEN1 was overexpressed in HCC tissues in comparison with the corresponding normal tissues (P < 0.01). FEN1 expression had positive correlations with differentiation degree (P=0.017), intrahepatic metastasis (P=0.046) and TNM stage (P=0.020) of HCC tissues. However, as regards gender (P=0.731), age (P=0.754), level of AFP (P=0.076) and tumor size (P=0.100) no significant differences were observed between the groups. FEN1 expression in HepG2 cells could be downregulated by siRNA effectively. Moreover, the inhibition of FEN1 expression suppressed the proliferation and induced the apoptosis of HepG2 cells(P < 0.05). Transwell migration assay suggested that the migration and invasion abilities of HepG2 cells were significantly inhibited when FEN1 was interfered (P < 0.05).

Conclusion FEN1 is abundantly expressed in HCC tissues, and abnormal FEN1 expression may associate with low differentiation grade, intrahepatic metastasis and poor patient prognosis. Downregulation of FEN1 expression reduced HCC cells proliferation and induced cells apoptosis, as well as, reduced HCC cells migration and invasion ability in vitro. FEN1 might be a novel target for hepatocellular carcinoma diagnosis and therapy.