Neoepitope-based Personalized DNA Vaccine Approach in Pediatric Patients With Recurrent Central Nervous System Tumors

Step 1 Eligibility Criteria for Tissue Sequencing Inclusion Criteria: * Any patient between the ages of 12 and 25 years of age (inclusive) who was diagnosed with any of the following: * High-grade glioma (HGG); newly diagnosed patients * Diffuse midline glioma (DMG); newly diagnosed patients * A pediatric CNS (brain or spine) tumor of any histologic subtype, who has now developed recurrent or refractory disease. * All patients enrolled in this trial will receive treatment for pediatric CNS tumors, including systemic agents, investigational agents, or radiation therapy, prior to receiving the neoantigen DNA vaccine. Co-enrollment to another interventional clinical trial is permitted during the vaccine manufacture period. * Availability of tissue for sequencing to determine presence of targetable neoantigen. This may be fresh tissue collected as part of routine care, another research project, or banked fresh frozen samples from tissue obtained at time of progression from a previous biopsy, subtotal resection, total gross resection, or re-resection, with the following disease specific restrictions: * For HGG and DMG patients, tissue may be collected either at diagnosis or after tumor recurrence or progression. * For pediatric CNS tumor patients, tissue must be collected after tumor recurrence or progression. * Life expectancy \> 24 weeks. * Ability to understand and willingness to sign an IRB approved written informed consent document (or that of legally authorized…