IMMU-12. ABERRANT EGFR SIGNALING IS ASSOCIATED WITH DIMINISHED CYTOTOXIC T-CELL INFILTRATION IN GLIOBLASTOMA PATIENTS

Abstract Glioblastoma (GBM) has not benefitted from recent advances in immunotherapy compared to other solid malignancies, which suggests that a deeper understanding of the immunobiology GBM is necessary develop better therapeutic options. Both oncogenic signaling and evasion immune destruction are hallmarks cancer, contributing tumor growth reduced survival, respectively. Despite evidence non-CNS malignancies demonstrating importance aberrant on shaping microenvironment, impact epidermal factor (EGFR) – genetically altered 60% patients - microenvironment well characterized GBM. To evaluate EGFR patient samples, we performed single-cell transcriptomic analysis primary infiltrating leukocytes (TILs) twenty-five revealed associated with unique both recurrent disease. Specifically, disease setting, higher infiltration macrophages dendritic cells, significantly lower T-regulatory cells was observed non-altered patients. In disease, alterations were diminished activated exhausted cytotoxic T-cells unaltered Intriguingly, differential gene expression display increased interferon stimulated genes (ISGs) myeloid lymphoid lineages, while compartment unexpectedly greater MHCI genes. Collectively, these data emphasize composition suggest further characterization EGFR-immune crosstalk mechanism warranted