Single-cell transcriptome profiling of the stepwise progression of head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) undergoes stepwise progression from normal tissue to metastasized tumors. To comprehensively delineate the heterogeneity of tumor cells and their interactions during the progression of HNSCC, we employed single-cell RNA-seq (scRNA-seq) profiling for the tissues of normal, leukoplakia, HNSCC, and metastasized HNSCC. We identified novel clones of malignant cells expressing LGALS7B and fibroblasts expressing CXCL8, and the abundance of these cells in the tumor tissue was associated with poorer prognostic outcomes. In addition, we demonstrated that fibroblasts in leukoplakia and tumor tissue express COL1A1, which interacts with CD44+ malignant cells, facilitating HNSCC progression. CD4+FOXP3+ regulatory T cells expand in leukoplakia and express LAIR2 with collagen stimulation, which may provide a favorable microenvironment for tumor progression. In conclusion, stromal and immune cell interactions play critical roles in the stepwise progression of HNSCC, and we have identified steps during HNSCC progression for possible therapeutic interventions Single-cell transcriptome profiling from 37 tissue specimens of non-tumoral surrounding normal tissue (NL, n = 9), leukoplakia (LP, n = 4), primary cancer (CA, n = 20), and metastatic tumors in lymph nodes (LN, n = 4)