1048 Molecular Diagnosis and Quantification of Tumor Cell Infiltration During Glioma Surgery Through Ultra-Rapid Droplet Digital PCR

INTRODUCTION: Class-defining clonal mutations occur in nearly all cases of adult low-grade gliomas and serve as critical prognostic and diagnostic biomarkers. The ability to unlock tumor mutational status at the time of surgery would significantly elevate the standard of surfgical and adjuvant care for brain tumor patients. However, rapid access to molecular data during surgery is not available, complicating accurate intraoperative diagnosis and detection of tumor cell burden at surgical margins. METHODS: In 50 specimens collected from 13 adult IDH- or BRAF-mutant glioma patients, we demonstrate the clinical feasibility of intraoperative UR-ddPCR assays for the IDH1 R132H and BRAF V600E clonal mutations. RESULTS: Combined with stimulated Raman histology, UR-ddPCR estimates tumor cell percentage (0-95.0%) and tumor cell burden (<1-1332 cells/mm2) in biopsies taken from tumor core and margins with accuracy comparable to a standard 3-hour ddPCR workflow (R2=0.996, p=5.5x10-57). CONCLUSIONS: The UR-ddPCR workflow presented herein represents a 12-fold increase in turnaround time from tissue to molecular detection compared to the current standard of care. With anticipated refinements in assay instrumentation, we anticipate that UR-ddPCR will enable a new standard in point-of-care molecular diagnostics and surgical precision at the cellular level.