Background: Previous reports show that phospholipase C epsilon-1 (PLCE1 ) expression is positively correlated with esophageal squamous cell carcinoma and gastric cardia adenocarcinomas; however, the expression of PLCE1  in hepatocellular carcinoma (HCC) and its correlation with clinical outcome still remain unclear. The aim of this study was to explore the expression of PLCE1  in HCC tissue and to determine whether PLCE1  was a prognostic factor for HCC patients.
Materials and methods: PLCE1  levels in 20 paired HCC tissues and corresponding paracarcinomatous tissues was investigated by quantitative real-time polymerase chain reaction and Western blot assays. In addition, protein levels of PLCE1  in one normal liver epithelial cell and four HCC cell lines were examined using Western blot assay. Moreover, immunohistochemistry was applied to determine the expression of PLCE1  in HCC and corresponding surrounding tissues from 90 patients. Statistical analyses were used to examine the association between PLCE1  levels and clinicopathological features.
Results: We found that the expression of PLCE1  in tumor tissues was significantly lower than those in paracarcinomatous tissues at both mRNA and protein levels (P <0.05). We also determined that PLCE1  protein expression levels were lower in HCC cell lines than normal liver epithelial cells (P <0.05). Notably, immunohistochemical assay showed that PLCE1  expression was significantly low in HCC tissues compared with the adjacent normal liver tissues (40% vs 18.9%; P <0.05). Besides, PLCE1  levels were negatively correlated with tumor capsulae, vascular invasion, Edmondson grade, alpha-fetoprotein, and tumor-node-metastasis stage (P <0.05). Univariate analysis revealed that lower level expression of PLCE1  was significantly associated with poorer overall survival (OS) rate (P <0.001) and disease-free survival rate (P <0.001). Multivariate analysis revealed that low PLCE1  level was an independent poor prognostic factor of OS and recurrence-free survival (P <0.001 and P =0.003, respectively).
Conclusion: In brief, our results revealed that decreased PLCE1  expression was associated with tumor progression in HCC and may function as a promising biomarker for HCC prognosis.
Keywords: PLCE1 , hepatocellular carcinoma, prognosis, immunohistochemistry