Expression of programmed death ligand-1 and programmed death 1 in hepatocellular carcinoma and its clinical significance

Objective: To investigate the correlation between the expression of programmed death 1 (PD-1) and PD ligand-1 (PD-L1) in hepatocellular carcinoma (HCC) and clinical parameters. Materials and Methods: The study comprised tumor sections from 45 HCC patients treated with curative resection, which were evaluated for PD-1 and PD-L1 protein expression by immunohistochemistry. Results: PD-1 and PD-L1 expression was increased in cancers compared to adjacent normal tissues, with a positive rate of 37.78% (17/45) and 62.22% (28/45), respectively, which was positively correlated with the tumor stage and lymph node metastasis, negatively with postoperative prognosis. PD-1 positivity was most frequently observed in stromal tumor-infiltrating lymphocytes. The number of PD-1 positive lymphocyte was correlated with PD-L1 positive expression. Conclusion: PD-L1 and PD-1 are overexpressed in HCC tissues. PD-L1 expression plays a critical role in the pathogenesis of human HCC, suggesting that it might be used as a new biomarker to predict the disease progression and prognosis.