The heterogeneity, developmental differentiation trajectories, and underlying molecular mechanisms of endothelial cells in penile squamous cell carcinoma (PSCC) remain inadequately understood. This study aims to further explore the heterogeneity of endothelial cells in penile cancer at single-cell resolution and investigate their potential contribution to tumor progression.

We collected matched tumor and adjacent normal tissue samples from five PSCC patients and performed single-cell RNA sequencing. Next, we employed multiplex immunofluorescence (mIF) staining to confirm the presence of SPRR1B+ endothelial cells (ECs) in tumor tissue from 34 penile cancer patients. We then explored the potential effects of PSCC tumor cells on endothelial cells through co-culture experiments and further investigated the biological role of SPRR1B+ ECs in the progression of PSCC in vitro.

In this study, we utilized single-cell RNA sequencing to profile the cellular landscape of PSCC. We identified a new subpopulation of endothelial cells (SPRR1B+ ECs) that highly expresses the epithelial cell marker SPRR1B. SPRR1B+ ECs are significantly upregulated in PSCC tumor tissues, particularly in the later stages of tumor progression. Clinical cases showed that high expression of SPRR1B+ ECs is associated with poor prognosis. Furthermore, functional experiments demonstrated that SPRR1B+ ECs promote the malignant progression of PSCC tumor cells through direct cell-cell contact.

In conclusion, our study discovered a group of SPRR1B+ ECs in PSCC tumor tissues, which are associated with advanced tumors and poor prognosis in PSCC patients. SPRR1B+ ECs were found to be induced by PSCC tumor cells in the tumor microenvironment and may interact with tumor cells through direct cell-cell contact (CD44-SELE pathway). Our work indicated that SPRR1B+ ECs may as a key subtype in PSCC progression and provides potential therapeutic avenues for PSCC treatment.