Spatial Transcriptomics Reveals a Molecular Tumor Budding Signature in Head and Neck Cancer
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ABSTRACT: Tumor budding is a histopathological feature associated with poor prognosis across multiple cancer types, including head and neck squamous cell carcinoma (HNSCC). Tumor buds represent the earliest traceable local invasion and are considered the origin of minimal residual disease, local recurrence, and metastasis. However, the molecular features underlying this phenomenon in HNSCC remain only partially characterized due to challenges in isolating tumor buds while preserving spatial context. Here, we employed high-plex spatial transcriptomics to specifically isolate and characterize tumor buds, complemented by single-cell RNA sequencing and pharmacogenomic analyses to comprehensively characterize the transcriptional landscape of tumor budding in human papillomavirus (HPV)-negative HNSCC. Our unprecedented spatial resolution revealed that tumor buds exhibited distinct gene expression profiles compared to tumor bulk, with significant upregulation of epithelial-mesenchymal transition (EMT) markers, extracellular matrix remodeling genes (including fibronectin and laminin-332 subunits), and coagulation pathway components. Unlike previous bulk tissue analyses, our approach enabled differential correlation analysis that uncovered extensive gene network rewiring both within tumor cells and between tumor and stromal compartments, highlighting dynamic molecular reprogramming during the budding process. We developed a novel 28-gene tumor budding signature (TBS) that effectively distinguished tumor buds from other compartments (AUC=0.97) and demonstrated independent prognostic value in the TCGA-HNSC cohort (HR=1.54, p=0.02), representing the first molecularly defined biomarker for tumor budding applicable to conventional transcriptomic data in HNSCC. Analyses of single-cell RNA-seq datasets confirmed the tumor-specific expression of the TBS, its association with a hybrid epithelial-mesenchymal state, its expression predominantly at the leading edges of tumors, and its induction via subtypes of epidermal growth factor receptor activities. Uniquely, our pharmacogenomic analysis revealed that SCC cell lines with high TBS scores showed increased sensitivity to Raf-MEK inhibitors, suggesting clinically actionable therapeutic vulnerabilities, which was confirmed in a 3D model of early local invasion. This integrated spatial-molecular approach provides novel insights into tumor budding in HNSCC and establishes a foundation for a better understanding of the molecular mechanisms of tumor budding, as well as improved risk stratification and targeted therapeutic interventions for this aggressive tumor phenotype.
ORGANISM(S): synthetic construct Homo sapiens
PROVIDER: GSE300414 | GEO | 2026/04/17
REPOSITORIES: GEO
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