FOS-like antigen 1 is a prognostic biomarker in hepatocellular carcinoma

Background/Aim: The prognosis of hepatocellular carcinoma (HCC) is very dismal and the targeted drugs of HCC are limited. Studies of HCC prognostic biomarkers have made little progress, though many new techniques such as high-throughput sequencing have been applied. FOS-like antigen 1 (FOSL1) is generally accepted as a proto-oncogene but its clinical significance in HCC has never been elucidated. Materials and Methods: In our study, we investigated the expression of FOSL1 in 114 paraffin-embedded HCC tissues, and detected FOSL1 mRNA levels in 20 pairs of fresh HCC tissues and their corresponding tumor adjacent tissues. The correlations between FOSL1 expression and clinicopathological factors were analyzed and the prognostic significance of FOSL1 was evaluated with univariate and multivariate analysis. Moreover, we detected the function of FOSL1 in HCC proliferation with experiments in vitro. Results: FOSL1 mRNAs in HCCs were significantly higher than those in tumor adjacent tissues. The percentage of high expression and low expression of FOSL1 accounted for 46% (53/114) and 54% (61/114), respectively. High expression of FOSL1 was significantly associated with larger tumor size (P = 0.021), hepatitis B virus infection (P = 0.014), advanced T stage (P = 0.014), and tumor necrosis metastasis stage (P = 0.014). Moreover, high expression of FOSL1 was significantly correlated with poor prognosis of HCC and could be identified as an independent prognostic biomarker of HCC (hazard ratio = 5.60, 95% confidence interval = 3.00–10.45, P < 0.001). With in vitro function assay, we demonstrated that FOSL1 played an essential role in HCC proliferation. Conclusions: High expression of FOSL1 is an independent risk factor of HCC predicting unfavorable prognosis, indicating that FOSL1 detection could stratify patients with high risk, and anti-FOSL1 therapy may be a promising way to treat HCC.