Programmed death‑ligand 1 expression is an unfavorable prognostic factor of hepatocellular carcinoma after archiving sustained virologic response for hepatitis C virus infection

The aim of the present study was to study the pathological prognostic factor of initial hepatocellular carcinoma (HCC) after archiving sustained virologic response (SVR) for hepatitis C virus (HCV) infection. A single-center retrospective analysis was performed for patients who underwent hepatectomy between 2003 and 2017. We studied clinico-pathological findings of resected liver tissues in 35 patients with HCC after SVR treated by interferon (IFN group) and 13 patients with HCC after SVR treated by direct acting antivirals (DAA group). We also performed immunohistochemical staining using antibodies against programmed death-ligand 1 (PD-L1), cytokeratin 19, epithelial cell adhesion molecule (EpCAM) and regulator of G-protein signaling 5 (RGS5). PD-L1 positive HCC was observed in 6 cases of the IFN group and 4 cases of the DAA group. In the IFN group, in univariate analysis of recurrence free survival after surgery (RFS), the PD-L1 expression had a statistically significant impact (HR=6.01; P=0.02). In the multivariate analysis of RFS, PD-L1 expression significantly remained (HR=5.01; P=0.03). For both RFS and overall survival, Kaplan-Meier curves confirmed that patients with PD-L1 expression showed significantly worse prognosis (log-rank test P<0.01). Nuclear grade, RGS5 expression, and EpCAM expression were significantly higher in the PD-L1-positive HCC group compared with the PD-L1-negative HCC group (P<0.05). Therefore, PD-L1 expression may be an independent prognostic factor of surgically resected HCC after achieving SVR.