Multi-omic profiling identifies malignant subpopulations and a hypoxia-driven angiogenic axis as therapeutic vulnerabilities in sinonasal squamous cell carcinoma

Sinonasal squamous cell carcinoma (SNSCC) is a rare and aggressive malignancy with limited treatment options, necessitating comprehensive molecular characterization to uncover actionable therapeutic targets. Here, we integrate bulk and single-cell transcriptomics, epigenomics, and DNA methylation profiling to construct a detailed molecular and cellular landscape of SNSCC. Our analysis identifies five transcriptionally and epigenetically distinct malignant subpopulations, including hypoxic (TC1) and proliferative (TC2) clusters, with TC1 showing significant association with poor clinical outcomes. We uncover a hypoxia-driven angiogenic axis, wherein TC1 cells secrete adrenomedullin (ADM), MIF, and VEGFA to activate endothelial tip cells, fostering tumor angiogenesis. Epigenetic reprogramming, characterized by alterations in DNA methylation and chromatin accessibility, underpins these transcriptional programs, with AP-1 transcription factors emerging as key regulators. Notably, ADM expression is epigenetically controlled, correlates with advanced clinical stage, and predicts reduced survival in head and neck cancer patients. This multi-omic study highlights the tumor heterogeneity and microenvironmental interactions driving SNSCC progression, revealing epigenetically regulated pathways as promising therapeutic targets for future intervention.