Circulating tumor DNA profiling for childhood brain tumors: Technical challenges and evidence for utility

Cell-free DNA (cfDNA) profiling as liquid biopsy has proven value in adult-onset malignancies, serving as a patient-specific surrogate for residual disease and providing a non-invasive tool for serial interrogation of tumor genomics. However, its application in neoplasms of the central nervous system (CNS) has not been as extensively studied. Unique considerations and methodological challenges exist, which need to be addressed before cfDNA studies can be incorporated as a clinical assay for primary CNS diseases. Here, we review the current status of applying cfDNA analysis in patients with CNS tumors, with special attention to diagnosis in pediatric patients. Technical concerns, evidence for utility, and potential developments are discussed.