Expression of programmed death receptor-1 ligand (PD-L1) in human cancer is of prognostic value and associated with macrophage infiltration

The tumor immune microenvironment is a crucial factor influencing tumor progression, and its molecular mechanisms have become a key topic in immunotherapy research. Programmed death receptor-1 ligand (PD-L1, CD274) is a well-known immunosuppressive molecule that can mediate the immune escape of tumor cells. The aim of this study was to evaluate the significance of PD-L1 in human cancer by integrated bioinformatics analysis. Tumor IMmune Estimation Resource (TIMER), GEPIA, Kaplan-Meier plotter, TISIDB and Tumor Immune Single Cell Hub (TISCH) were used to perform the corresponding analysis. The results showed that PD-L1 was dysregulated in various cancers and was associated with the overall survival of cancer patients, which was associated with macrophage infiltration levels. Moreover, PD-L1 expression showed a significant correlation with macrophages and was universally expressed on tumor-associated macrophages (TAMs). Notably, the expression of PD-L1 on TAMs was found to be correlated with immunotherapy response in certain cancers based on analysis of single-cell RNA sequencing data. In conclusion, PD-L1 plays a significant role in cancer, which may partly be influenced by TAMs.