Exploratory spatial transcriptomic profiling of peritumoral Th2 immune polarization in HPV-positive oropharyngeal cancer.

Introduction: Oropharyngeal squamous cell carcinoma (OPC) associated with high-risk human papillomavirus (HPV), particularly HPV-16, generally shows favorable outcomes yet paradoxically exhibits a high incidence of early lymphatic metastasis. The immune mechanisms underlying this phenomenon remain unclear. Methods: We conducted an exploratory spatial transcriptomic analysis using the GeoMx Digital Spatial Profiler on formalin-fixed, paraffin-embedded samples from six patients with palatine tonsil-derived OPC. Tumor tissue regions (TTRs) and lymphoid follicular regions (LFRs) were compared according to HPV status and nodal involvement. Results: In HPV-positive LFRs, pathways related to B-cell apoptosis appeared downregulated, suggesting prolonged B-cell survival and antigen presentation. Metastasis-negative HPV-positive cases displayed a Th2-skewed immune profile in LFRs, with increased naïve B cells, plasma cells, eosinophils, M2 macrophages, and activated mast cells. In contrast, metastasis-positive cases showed increased T cell activation in LFRs and reduced proliferation-related signaling in TTRs. Pathways involving estrogen signaling and bile acid metabolism were also associated with metastatic behavior. Conclusion: These exploratory findings suggest that peritumoral Th2-biased immunity within lymphoid structures may contribute to restraining lymphatic metastasis in HPV-positive OPC. Spatial transcriptomics may provide a high-resolution framework for investigating tumor-immune interactions and generating hypotheses for future mechanistic and clinical studies.