Single-cell analysis reveals potential therapeutic markers of peripheral blood mononuclear cells from bladder cancer patients

Bladder cancer is the most prevalent malignancy of the urinary tract, with significant advancements in treatment achieved over recent decades. Nonetheless, the immunological mechanisms underlying bladder cancer progression remain elusive, and only a limited number of patients derive benefit from current immune checkpoint inhibitors. Here, we conducted a single-cell RNA sequencing analysis of 44,022 cells from peripheral blood mononuclear cell samples of bladder cancer patients and a healthy donor. Our findings indicated that the proportions of T cells and neutrophils are higher in bladder cancer patients than in the healthy donor. LAG3, HAVCR2, and CTLA4 had elevated expression levels in CD8-T2-GZMK cell clusters from patients. CD8-T7-STMN1 cells highly expressed ITGAE, CD38, and STMN1. Furthermore, NK3-CMC1, more prevalent in patients, showed a high expression of TIGIT. Additionally, Bcell2-TCL1A and Bcell3-MS4A1 were characterized by the high expression of inhibitory receptor marker genes. Gene set variation analysis suggested that Mono4-THBS1 may play a role in promoting tumor hypoxia and angiogenesis. Neu-FCGR3B exhibited high levels of IL4R and CD274 expression. Our study indicated that LAG-3 and TIM-3 may serve as novel potential immune checkpoint inhibitors in bladder cancer treatment. The phenotypes of NK3-CMC1, Bcell2-TCL1A, and Bcell3-MS4A1 might be altered by tumor progression. Mono4-THBS1 could potentially be a source of tumor-enriched monocyte-like cells. Neu-FCGR3B may play a detrimental role in the anti-tumor response and could emerge as a predictive marker for bladder cancer. Overall, these high-resolution transcriptomic data offer invaluable insights for identifying new therapeutic targets and biomarkers in bladder cancer immunotherapy.