Immune Microenvironment and Clinical Significance of PD1 Expression in Hepatocellular Carcinoma Patients

Immune checkpoint inhibitors (ICI) have revolutionized treatment for hepatocellular carcinoma (HCC), however, durable response is limited to only a subset of patients. Therefore, this study aims to identify the ICI-responsive HCC patients and to investigate the distribution of programmed death 1 (PD1) in HCC patients, as well as the relationship among PD1, pathological parameters and survival of HCC patients. A total of 372 HCC patients (western population) from The Cancer Genome Atlas (TCGA), 115 Primary HCC tissue and 52 para-carcinoma tissue (Data Set GSE76427, eastern population) from Gene Expression Omnibus (GEO) database were enrolled. Bioinformatics analysis were conducted with R software and Tumor Immune Estimation Resource (TIMER). This study showed the expression of PD1 was up-regulated in both western and eastern HCC patients, which was positively correlated with patients’ BMI and AFP value, as well as prognosis. The expression level of PD1 was significantly correlated with immune cell infiltration. Our study reveals the relationship of PD-1 and the HCC tumor microenvironment, providing insight for new ICI therapeutic options. Besides, PD1 expression levels in hepatocellular carcinoma (HCC) patients may be a survival predictor.