Protein translation dysregulation and immune cell evasion mediated by IFN and immunoproteasome downregulation define metastatic clones in HPV-related cancer of the oropharynx.

BACKGROUND: Human papillomavirus (HPV)-associated oropharyngeal cancer (OPC) is increasing in prevalence, but the drivers of metastasis remain poorly understood, which impacts the ability to personalise management decisions. Much of the genomic research to date focuses on the HPV-negative population. Here, we utilise single-cell and spatial single-cell techniques to understand the drivers of metastasis. METHODS: Patients with HPV-positive OPC and cervical lymph node metastases treated with curative surgery had matched samples from the primary and lymph nodes collected for research. Single-cell RNA sequencing, single-cell spatial sequencing (Visium) and in-situ spatial platforms were performed. Cancer clones were delineated using inferred copy number variation. Expression phenotypes and interactions with the tumour microenvironment were compared between the metastasising and non-metastasising cancer clones. RESULTS: Individual cancer clones have varied abilities to metastasise and undergo clonal expansion in the lymph node, with only a subset of clones present in the primary expanding in the lymph node. Four mechanisms were identified as defining the metastatic phenotype, including protein translation adaptation, immunoproteasome dysfunction and immune evasion, suppression of the IFN immune response and cap-independent protein translation. CONCLUSIONS: This research elucidates multiple mechanisms driving the expansion of cancer clones in HPV-positive oropharyngeal cancer. By detailing the roles of translational adaptation, immunoproteasome dysfunction, suppression of the interferon immune response and cap-independent protein translation, we provide insights into how these processes contribute to immune evasion and tumour survival.