Single-cell transcriptomics reveals a complex cell-cell communication network driven by myofibroblast-derived collagen in esophageal squamous cell carcinoma.

Fibroblasts are pivotal regulators of tumor development, progression, and therapeutic resistance in human malignancies. However, their functional diversity and cellular heterogeneity in esophageal squamous cell carcinoma (ESCC) remain largely elusive. In the present study, we constructed a high-resolution single-cell transcriptomic atlas of the ESCC tumor microenvironment (TME) via single-cell RNA sequencing of 15 tissue specimens derived from 8 ESCC patients. A distinct collagen-synthesizing myofibroblast subpopulation, termed Fibro_myo_C1, was identified as a potentially important fibroblast subset driving ESCC progression. This subset exhibited robust expression of collagen- and fibronectin-encoding genes including COL1A1, COL1A2, COL3A1, and FN1. Functionally, Fibro_myo_C1 might promote epithelial-mesenchymal transition in malignant cells, enhance angiogenesis in endothelial cells, and induce an immunosuppressive TME by recruiting Tregs, exhausting CD8+ T cells, and polarizing M2-like macrophages. Clinically, high infiltration of Fibro_myo_C1 was significantly correlated with poor neoadjuvant immunotherapy response in ESCC patients. In conclusion, our study reveals Fibro_myo_C1 as a prominent fibroblast subset associated with ESCC progression that orchestrates stromal crosstalk to drive malignancy, angiogenesis, and immune suppression. Targeting Fibro_myo_C1 may represent a promising therapeutic strategy to reverse immunotherapy resistance and improve clinical outcomes for ESCC patients.