Single-cell sequencing reveals cellular composition and tumor microenvironment alterations across risk stratification...

Cutaneous squamous cell carcinoma (cSCC) is a metastatic-prone malignancy where risk stratification guides management. However, current stratification lacks robust biological underpinnings, limiting its ability to predict progression and tailor therapies. The molecular drivers of tumor microenvironment (TME) evolution across risk strata remain elusive, hindering personalized approaches.

Single-cell sequencing and clinical risk profiling were integrated to dissect tumor TME dynamics underlying cSCC progression across risk strata.

The very high-risk group exhibited a skewed neutrophil-to-lymphocyte ratio and progressive depletion of γδT cells, a subset linked to anti-tumor surveillance. Concurrently, cancer-associated fibroblasts (CAFs) displayed risk-dependent enrichment, with inflammatory CAFs (iCAFs) predominating in advanced stages, suggesting their role in fostering immune suppression and metastasis. Further, dysregulation of CXCL8 (pro-inflammatory chemokine), TGFβ (matrix remodeling), and IGFBP7 (stromal crosstalk) emerged as hallmark transcriptional features of very high-risk tumors, correlating with epithelial-mesenchymal transition.

This study establishes iCAFs and γδT cell loss as central drivers of cSCC aggressiveness and nominates CXCL8/TGFβ/IGFBP7 dysregulation as a biomarker framework for risk stratification. Collectively, these findings unveil actionable therapeutic targets and provide a molecular basis for personalizing management strategies, particularly for identifying and treating very high-risk cSCC patients who may benefit from intensified surgical approaches, adjuvant therapies, or novel targeted interventions.