PSMA1, PSMA5, and PSMB2 serve as prognostic biomarkers and are correlated with tumor-infiltrating leukocytes in HCC

Hepatocellular carcinoma (HCC) ranks as the third leading cause of cancer-related death. Proteasome (PSM) is the main intracellular proteolytic system in higher eukaryotic cells. It has been reported to be involved in the tumor's onset, metabolism, and survival, and it has been recognized as a therapeutic target for many human cancers. The 20S proteasome subunits, specifically proteasome 20S subunit alpha 1 (PSMA1), proteasome 20S subunit alpha 5 (PSMA5), and proteasome 20S subunit beta 2 (PSMB2), are overexpressed in various malignancies, including HCC. Nevertheless, the exact role of these genes in HCC prognosis remains only partially understood. Moreover, a reliable predictive biomarker for HCC is essential for supporting the implementation of personalized therapies. Therefore, this study employed a comprehensive bioinformatics approach, integrating data from cBioPortal, Human Protein Atlas (HPA), Oncomine, STRING Viruses, Kaplan-Meier plotter, and other established high-throughput databases and tools. The current study thoroughly examined the expression levels, methylation, and genomic alterations of PSM and their correlation with tumor-infiltrating leukocytes. PSMA1, PSMA5, and PSMB2 are overexpressed in various cancers, including HCC, and their expression levels are associated with tumor grade and stage. The abundance of these genes is linked to diminished DNA methylation levels and genome alterations. Moreover, there was a significant association between the expression levels of these genes and poor prognosis and immune cell infiltration. In conclusion, this study proposes PSMA1, PSMA5, and PSMB2 as biomarkers for HCC.