BIOM-17. SPYING ON GLIOMAS: LONGITUDINAL CSF AS A PLATFORM FOR GLIOMA MONITORING AND RESPONSE BIOMARKER DISCOVERY

Abstract The relative inaccessibility of a patient’s glioma throughout their disease course precludes individualized insights into tumor biology and responses thereof to therapeutic challenge. We propose that serial cerebrospinal fluid (CSF) samples can be used perform espionage in the form biomarker discovery for analytes are sensitive burden (for monitoring) candidate therapies biological impact). To end, we routinely leveraging neurosurgical access CNS collect CSF intraoperatively from chronically implanted Ommaya reservoirs longitudinal (NCT04692337, NCT04692324). Global proteomic analysis was performed on Somalogic platform – an aptamer-based technology highly specific over 7,000 proteins. Using each ranked protein list (glioma vs. 3 control patients), enrichment cohort five patients identify conserved proteins glioma. reveal monitoring, further decreased with resection increased recurrence, using two sets paired patient samples. Forty-four met these criteria; this high-grade signature significantly enriched independent twelve (FDR=0 all patients). HGG abundance following other patients, confirming burden. Top included LANC2, DPYL3, Sorcin, Integrin A1B1, lactate dehydrogenase (FC control: 145.3x, 113.9x, 78.0x, 71.6x, 62.7x, respectively). Interestingly, despite having explicitly chosen little-to-no hemoglobin cohort, plasma-like (FDR=0), suggesting potential impact blood-brain barrier disruption extracellular proteome. In conclusion, our data demonstrate proteome feasibly accessed (“espionage”) via serially-acquired