A highly resolved integrated single-cell atlas of HPV-negative head and neck cancer

Head and Neck Squamous Cell Carcinomas (HNSCC) are the seventh most prevalent form of cancer and are associated with human papilloma virus infection (HPV-positive) or with tobacco and alcohol use (HPV-negative). HPV-negative HNSCCs have a high recurrence rate, and individual patients' responses to treatment vary greatly due to the high level of cellular heterogeneity of the tumor and its microenvironment.

Here, we describe a HPV-negative HNSCC single cell atlas, which we created by integrating six publicly available datasets encompassing over 230,000 cells across 54 patients. We classify cell types, subpopulations, and their expression programs in the immune, mesenchymal, endothelial and epithelial compartments. We interrogate the relationship between cell types through hierarchical clustering, cell-cell communication analysis and correlating populations changing together across patients.

We resolve the myeloid and fibroblast compartments, revealing an IL1B+ myeloid population previously unexplored in HNSCC and clarifying two immune cancer associated fibroblast populations that are frequently conflated, identify sex-associated changes in cell type proportions, and a unique interaction between CXCL8-positive fibroblasts and vascular endothelial cells.

We utilize the atlas to contextualize the relationships between existing signatures and cell populations, harmonize nomenclature across studies, and show the power of this large-scale resource to robustly identify associations between transcriptional signatures and clinical phenotypes that would not be possible to discover using fewer patients. Beyond our findings, the atlas serves as a public resource for the high-resolution characterization of tumor heterogeneity of HPV-negative HNSCC.