Immunopeptidomics in gliomas: Decoding antigen presentation for precision immunotherapy.

Gliomas and particularly glioblastomas, represent the most aggressive and treatment-resistant brain tumours. Current standard treatments, including surgical resection, radiotherapy and chemotherapy, offer only limited long-term survival benefits. The highly immunosuppressive tumour microenvironment that characterizes gliomas enables immune evasion and limits the effectiveness of anti-tumour immune response, indicating the urgent need for identification of tumour antigens with clinical relevance to improve current immunotherapeutic strategies and enhance glioma immunogenicity. Immunopeptidomics, a mass spectrometry-based identification of peptides presented by HLA molecules, is a growing field of research for understanding the immunosurveillance of gliomas. By enabling the direct identification of naturally presented HLA-bound peptides from tumour tissue for T cell recognition, immunopeptidomics provide valuable insights into tumour antigen presentation and immune targeting. This review highlights the emerging role of immunopeptidomics in gliomas, covering the mechanisms of antigen processing and presentation by HLA class I and II molecules, the identification of glioma-associated antigens, the development of personalised peptide vaccines and the discovery of new targets for T cell-based immunotherapies. The potential of plasma-derived soluble HLA (sHLA) peptidomes as minimally invasive liquid-biopsy biomarkers is further discussed for disease monitoring and response to treatment. Overall, immunopeptidomics are foreseen as a powerful tool for the discovery of new tumour antigens leading to the development of more effective personalised glioma immunotherapies.