Single-cell immunoprofiling reveals a dysfunctional-like immune microenvironment and malignant phenotype in aging penile squamous cell carcinoma

BACKGROUND: Penile squamous cell carcinoma (PSCC) can affect men of any age, but we know little about the differences between non-old and old patients with PSCC, which severely limits the precise diagnosis and treatment of PSCC. METHODS: We collected 2 non-old and 3 old PSCC samples and performed single-cell RNA sequencing and single-cell TCR-Seq analysis. All samples were subjected to UMAP clustering, and subcluster analyses were carried out on tumor cells, T cells, and myeloid cells. Furthermore, cell trajectory analyses were completed for tumor cells and T cells. We performed immunohistochemistry for DCN, KITLG, GPX4, and EPCAM and immunofluorescence for CD24 and MIF, as well as Masson staining and β-galactosidase staining on tissues. Macrophages were cultured for flow cytometry to detect the expression of HLA-DR on the cell surface after MIF treatment. RESULTS: We found that tumor cells in older PSCC demonstrated a more pronounced senescence-associated secretory phenotype (SASP) and gave rise to a subcluster of senescence-associated tumor cells, which exhibited stronger malignant features. Interestingly, we observed similar alterations in old head and neck squamous cell carcinoma (HNSC) samples. In addition, older PSCC samples also had more dysfunctional-like CD24 + T cells and more angiogenic macrophages. Finally, we revealed enhanced MIF signaling between fibroblasts and other cells to be another significant feature of aging PSCC. CONCLUSIONS: Our study systematically addressed the effects of aging on PSCC and identified IL1B as a potential prognostic marker for PSCC, offering a framework for the classification management and treatment of PSCC patients.