Project Summary/Abstract Gliomas are a heterogeneous group of tumors with diverse clinical outcomes. While isocitrate dehydrogenase mutation (IDH-MT) and other genetic features of glioma have changed the landscape of diagnosis and prognosis for lower-grade glioma, these same markers do not explain heterogeneity in treatment response and survival for glioblastoma (GBM). Individual immune factors may play a role in glioma outcomes. To address this, we have pioneered immunomethylomics, an approach that defines and quantitates an extended library of immune cell populations (e.g., naïve and memory CD4, CD8 T-cells, and B cells, NK cells, monocytes, neutrophils) and aberrant myeloid-derived suppressor cells (MDSCs) from fresh or frozen peripheral whole blood. Immunomethylomics is a powerful methodology based on DNA methylation patterns in the immune cell genomes. In this renewal, we will use immunomethylomics to address high-priority and yet unresolved clinical problems in GBM patient management using three aims. In Aim 1, we propose to develop an algorithm for stratifying GBM patients according to expected survival. Historically, individual measures were used, i.e., age, IDH-MT (<10% of GBMs), and DNA methyltransferase (MGMT) methylation. Important gaps in this univariate approach include the lack of assessment of corticoid steroid immunosuppression and the influence of MDSCs. We will address these gaps by creating integrated IDH-Wildtype (IDH-WT) GBM survival models with longitudinal immune profile data. In Aim 2, we will create a blood-based stratification of glioma subgroups by IDH status and grade. The current lack of methods to identify tumor IDH status before surgery limits neoadjuvant and intraoperative therapeutic strategies that are increasingly important in clinical trial design. Aim 2 addresses this unmet need. In Aim 3, we will create predictive blood biomarkers for response to immunotherapy and radiation. Non-invasive predictors are urgently needed to help distinguish radiologic evidence of early true progression (~30% of GBM patients) from pseudoprogression (PsP; ~20-30%). Uncertainty about true progression vs. PsP based on magnetic resonance imaging (MRI) alone results in patients being subjected to the risk and expense of re-operation for further management. Our and others’ recent studies demonstrate that both PsP and GBM survival are influenced by patient immunologic factors, specifically, the concentrations of MDSCs that accumulate in peripheral blood. Aim 3A addresses this unmet need by creating a blood-based biomarker to distinguish PsP from true progression in GBM patients after chemo/radiation. There are no standardized comprehensive methods to assess the effect of the systemic immune system on response to immunotherapies. In Aim 3B we test our methodology in four clinical trials representing two different immunotherapy modalities (anti-PD1/PD-L1 and CART adoptive cell therapy). In summary, this project will continue to identify ...