Identification of CD159A as a prognostic and immune biomarker in kidney renal clear cell carcinoma.

Kidney renal clear cell carcinoma (KIRC) is a highly aggressive malignant tumor, and its occurrence and progression are influenced by tumor microenvironment (TME). CD159A, a natural killer (NK) cell inhibitory receptor, has emerged as a critical immune checkpoint in TME. We conducted a comprehensive multi-omics analysis of CD159A expression, prognostic significance, and functional enrichment in KIRC. Additionally, quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC) were employed to perform CD159A expression in the Xiangya KIRC validation cohort. Furthermore, in vitro experiments were evaluated through cell proliferation, colony formation, and flow cytometry (FC) analysis of apoptosis in KIRC cell lines. Our study found that CD159A expression was significantly upregulated in KIRC tissues compared to normal tissues, as confirmed by TCGA data and the Xiangya KIRC validation cohort. In machine learning analyses, the biological significance of the regulatory network risk factors of the CD159A-HLA-E pathway is immunosuppressive receptors or abnormal antigen presentation that may promote immune escape. Elevated CD159A levels were observed in NK cells and CD8(+) T cells infiltrating KIRC by single-cell RNA sequencing analysis. A positive correlation between CD159A and NK/CD8(+) T cell infiltration was observed, and higher CD159A expression in KIRC patients receiving anti-PD-1/PD-L1 immunotherapy was associated with improved outcomes. In vitro experiments demonstrated that silencing CD159A significantly suppressed proliferation, colony formation and induced apoptosis in KIRC cells. Our research highlights the critical role of CD159A as a key immune checkpoint in KIRC progression and immune evasion, suggesting its potential as a prognostic and immunotherapy biomarker.