Testing Cerebrospinal Fluid for Cell-free Tumor DNA in Children, Adolescents, and Young Adults With Brain Tumors

This is a multicenter study for children and young adults with primary brain tumor. All children and adolescent/young adult (AYA) patients 21 years of age are eligible. AYA patients \< 40 are eligible with a primary brain tumor entity more common in children than adults. Up to 300 people will take part in this study. Pediatric central nervous system (CNS) tumors represent a wide range of disorders and continue to be the leading cause of cancer-related death in children and adolescents. The past few years have led to a dramatic shift in the diagnosis and pathological classification of pediatric CNS tumors. Molecular biomarkers which are now being incorporated into treatment decisions and clinical trial design. With this, the need for longitudinal molecular monitoring of disease becomes increasingly evident. The anatomical challenges in accessing pediatric CNS malignancies coupled with the move toward molecular sub-classification and molecular targeted therapies leads to an urgent need to develop a non-invasive way to repeatedly sample these tumors. This would enable: 1) diagnose tumors that are surgically inaccessible; 2) monitor molecular changes in tumor longitudinally, including at progression and/or recurrence; and 3) develop non-invasive ways to monitor treatment responses. Recent advances in technology have allowed for the detection of cell-free tumor DNA (cfDNA), i.e., small fragments of tumor DNA, shed into the cerebrospinal fluid (CSF) and bloodstream in brain tumor patients through a process known as "liquid biopsy". Based on the successful preliminary studies in adult glioma patients, this Pediatric Brain Tumor Consortium (PBTC)-sponsored effort will attempt to integrate CSF cfDNA liquid biopsies into the clinical care of pediatric brain tumor patients across the PBTC to enhance tumor diagnosis/molecular subclassification and guide therapeutic decision making. This will be accomplished through centralized collection and processing of CSF cfDNA samples from patients with various types of pediatric CNS tumors across PBTC member sites. The primary objective will be to investigate the concordance between CSF cfDNA alterations and tumor DNA alterations in matched pairs to understand: 1) the concordance across matched samples; and 2) the genomic evolution that occurs over time across various tumor types. Additionally, the secondary objectives and exploratory objectives in this study are intended to aggregate data across various types of pediatric primary brain tumors to understand the rate of success of CSF cfDNA molecular profiling in different disease types and at various stages of disease, and to elucidate the role of CSF cfDNA profiling in guiding clinical decision making. The primary objective of this study is to estimate the concordance of mutations detected in the tumor tissue vs. cerebrospinal fluid cell free DNA (CSF cfDNA) across samples collected within 8 weeks of each other; determine whether clonal mutations are likely to be shared across sample types. Patients who have CSF samples taken as part of regular care will be asked to provide extra samples for this study. The study doctor will collect a minimum of one extra tube of CSF (about 1 teaspoon or 5 mL) for this study. If the patient's doctor thinks it is safe, up to 2 tubes of CSF (about 4 teaspoons or up to 20 mL) may be collected. A required blood sample (about ½ a teaspoon or 2 - 3 mL) will be collected once at the start of the study. An optional tumor tissue if obtained within 8 weeks of CSF collection will be collected if available. There is no treatment provided on this study.