EP08.01 THE IMMUNE LANDSCAPE OF BRAIN TUMORS: IMPLICATIONS FOR NEUROIMMUNOLOGY AND NEURO-ONCOLOGY THERAPIES

Abstract BACKGROUND Glioblastoma multiforme (GBM) is an aggressive brain tumor with a poor prognosis despite standard treatments. GBM evades immune responses through tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), and immune checkpoints like PD-1/PD-L1. The blood-brain barrier (BBB) further limits immune infiltration and drug delivery. Understanding GBM’s immune landscape is crucial for developing effective immunotherapies. MATERIAL AND METHODS A systematic review was conducted using PubMed and MEDLINE, focusing on GBM immunology and immunotherapies. Relevant clinical trials, meta-analyses, and preclinical studies published in the last 20 years were analyzed. Non-GBM studies and those lacking significant evidence were excluded. RESULTS GBM promotes immune evasion through TAM polarization, MDSC accumulation, and checkpoint upregulation, leading to T-cell suppression. Immune checkpoint inhibitors (ICIs) like nivolumab show limited success, benefiting only a subset of patients. Adoptive T-cell therapy (ACT) and oncolytic viruses show promise but face challenges like T-cell exhaustion and inconsistent clinical responses. Cancer vaccines, particularly targeting EGFRvIII, yield mixed results. Combination therapies, such as ICIs with radiotherapy, improve immune responses and tumor control. CONCLUSION GBM’s immunosuppressive environment remains a major treatment obstacle. Immunotherapies, including ICIs, ACT, and oncolytic viruses, show potential but require further optimization. Future research should focus on combination approaches and strategies to overcome immune resistance and BBB limitations. Advancing personalized immunotherapy and tumor profiling may enhance treatment outcomes for GBM patients.