Purpose

Hepatocellular carcinoma (HCC) is one of the most aggressive malignancies. Recently, the overexpression of programmed cell death 1 (PD-1) and PD-1 ligand 1 (PD-L1) has been shown to correlate with poor prognosis in many cancers. However, the expression of PD-L1 or PD-1 ligand 2 (PD-L2) and clinical outcomes have not been fully investigated in HCC.

Materials and Methods

Formalin-fixed paraffin-embedded samples were obtained from 85 patients with HCC who underwent surgery. The expression of PD-Ls (PD-L1, PD-L2) was evaluated by immunohistochemical analysis.

Results

The proportion of high expression groups of PD-L1 and PD-L2 was 27.1% and 23.5%, respectively. Univariate analysis revealed that tumor size (p< 0.001), histological differentiation (p= 0.010), PD-L1 expression (p< 0.001), and PD-L2 expression (p= 0.039) were significant prognostic factors of overall survival in patients with HCC. Multivariate analysis revealed that overall tumor size (hazard ratio [HR], 4.131; 95% confidence interval [CI], 2.233 to 7.643; p< 0.001 and HR, 3.455; 95% CI, 1.967 to 6.067; p< 0.001) and PD-L1 expression (HR, 5.172; 95% CI, 2.661 to 10.054; p< 0.001 and HR, 3.730; 95% CI, 1.453 to 9.574; p= 0.006) were independent prognostic values for overall and disease-free survival. Patients with high expression of PD-Ls had a significantly poorer survival than those with low expression (p< 0.001, p= 0.034).

Conclusion

The overexpression of PD-Ls in HCC patients is correlated with survival and tumor recurrence. Further evaluation of PD-1 and PD-Ls as therapeutic targets and predictive biomarkers for HCC is warranted.