Single-cell combined bioinformatics analysis: construction of immune cluster and risk prognostic model in kidney renal clear cells based on CD8 T cell-associated genes.

Background: Kidney cancer is an immunogenic solid tumor, characterized by high tumor burden and infiltration of CD8 T cells. Although immunotherapy targeting the PD1/CTLA-4 axis has demonstrated excellent clinical efficacy, clinical outcomes in most patients are poor.

Methods: We used the RNA sequencing data from the GEO database for KIRC GSE121636 and normal kidney tissue GSE131685, and performed single-cell analysis for cluster identification, pathway enrichment, and CD8 T cell-associated gene identification. Subsequently, the significance of different CD8 T-cell associated gene subtypes was elucidated by consensus clustering, pathway analysis, mutated gene analysis, and KIRC immune microenvironment analysis in the TCGA-KIRC disease cohort. Single gene analysis identified LAG3 as the most critical CD8 T-cell-associated gene and its function was verified by cell phenotype and immunohistochemistry in KIRC.

Results: In the present study, CD8 T-cell associated genes in KIRC were screened, including GZMK, CD27, CCL4L2, FXYD2, LAG3, RGS1, CST7, DUSP4, CD8A, and TRBV20-1 and an immunological risk prognostic model was constructed (risk score =  - 0.291858656434841*GZMK - 0.192758342489394*FXYD2 + 0.625023643446193*LAG3 + 0.161324477181591*RGS1 - 0.380169045328895*DUSP4 - 0.107221347575037*TRBV20-1). LAG3 was identified and proved as the most critical CD8 T cell-associated gene in KIRC.

Conclusion: We proposed and constructed an immunological risk prognostic model for CD8 T cell-associated genes and identified LAG3 as a pivotal gene for KIRC progression and CD8 T-cell infiltration. The model comprehensively explained the immune microenvironment and provided novel immune-related therapeutic targets and biomarkers in KIRC.