A Unified Single-Cell Atlas of HNSCC: Uncovering HPV and Sex Variability in the Tumor Microenvironment

Abstract

Head and neck squamous cell carcinoma (HNSCC) is highly heterogeneous, with variations driven by HPV status and sex. However, existing single-cell RNA sequencing (scRNA-seq) studies are often limited in sample size and lack standardized methodologies, limiting cross-study comparisons. To address this, we integrated scRNA-seq data from 78 patients (274,911 cells) across multiple studies, creating a unified HNSCC atlas that harmonizes annotations and enables robust tumor microenvironment (TME) analyses. Using STACAS for semi-supervised integration and automated annotation tools such as Ikarus and scGate, we improved tumor and immune cell classification. Leveraging our atlas, we identified HPV- and sex-specific shifts in immune and stromal composition, with HPV+ tumors enriched in adaptive immune cells and HPV- tumors showing more stromal and myeloid populations. Preliminary sex-stratified analyses suggested distinct microenvironmental patterns, warranting further investigation. This publicly available atlas provides a comprehensive framework for reproducibly studying HNSCC biology, improving patient stratification, and may help informing personalized therapies.