Single-Cell Sequencing Reveals Cellular Composition and Tumor Microenvironment Alterations Across Risk Stratification in Cutaneous Squamous Cell Carcinoma
Cutaneous squamous cell carcinoma (cSCC) is a malignant proliferation of the skin epithelium, constituting 20% of all non-melanoma skin cancers, and represents a significant threat due to its potential to metastasize to any organ in the body. Consequently, a more comprehensive understanding of cSCC is essential for improving preventive strategies and developing curative therapeutic approaches. Clinically, cSCC is stratified into lowrisk, highrisk, and very highrisk groups based on risk factors, with each category being closely associated with lymph node involvement, metastasis, and prognosis. However, the precise mechanisms governing the progression of cSCC across different risk levels remain inadequately elucidated. Examining the cellular composition and tumor microenvironment alterations across varying cSCC risk levels is critical for identifying key drivers of disease progression. In this study, single-cell sequencing was performed on tumor tissues from 2 lowrisk, 3 highrisk, and 2 very highrisk cSCC patients, encompassing a total of 65, 620 cells. The analysis revealed that as risk levels increased, there was a progressive rise in the neutrophil-to-lymphocyte ratio, accompanied by significant changes in the tumor microenvironment. Specifically, the proportions of iCAFs cells and Neutrophis increased with elevated risk levels, while the number of gamma delta cells decreased, suggesting these as potential therapeutic targets for cSCC. Further analyses focused on the CXCL8, TGF-beta and IGFBP7, with immunohistochemistry results corroborating a marked dysregulation of these genes in very highrisk tissues, indicating their potential as prognostic biomarkers for cSCC progression. This study not only advances the understanding of the molecular mechanisms underlying cSCC risk stratification but also provides valuable resources and potential biomarkers for therapeutic intervention.