Programmed cell death‐ligand 1 expression in hepatocellular carcinoma and its correlation with clinicopathological characteristics

BACKGROUND AND AIM: Programmed cell death‐ligand 1 (PD‐L1) immunohistochemistry score has been approved as the predictive biomarker for anti‐PD1/PD‐L1 therapy in several advanced malignancies. Although its predictive role remained inconclusive in hepatocellular carcinoma, ongoing study of anti‐PD1/PD‐L1 therapy showed promising results. However, less is known about the PD‐L1 immunohistochemistry score and factors correlated with it in hepatocellular carcinoma. We investigated PD‐L1 immunohistochemistry scores in a large cohort of hepatocellular carcinoma, as well as its correlation with various clinical and genomic factors. METHODS: Immunohistochemistry was performed to detect the expression of PD‐L1 protein in 315 hepatocellular carcinoma tissues. All slides were independently reviewed by three senior pathologists. Next‐generation YS panel (450 genes) sequencing was performed on 309 patients. RESULTS: Higher PD‐L1 expression as measured by combined positive score (CPS) was associated with increased Edmondson–Steiner grade (grade III vs II, P = 0.041) and TP53 mutations (P = 0.021). PD‐L1 CPS had no correlation with tumor mutational burden (Spearman's correlation coefficient 0.067). PD‐L1 CPS was not significantly associated with hepatitis B virus infection. CONCLUSIONS: Our data indicated that patients with higher Edmondson–Steiner grade (grade III) had significantly higher PD‐L1 CPS than patients with lower Edmondson–Steiner grade (grade II). Patients with TP53 mutations had significantly higher PD‐L1 expression.