13. DESCRIPTION OF INFORMED CONSENT PROCESS Study site personnel will identify potentially eligible subjects who are scheduled for craniotomy due to recurrent MB/PNET and initially screen eligibility and interest in possible protocol participation. In select cases, patients at outside institutions who have had surgical resection and tumor tissue snap frozen and available for TTRNA will be screened for eligibility and possible protocol participation. Dr. Mitchell (or his designee) of the UF Brain Tumor Immunotherapy Program and D epartment of Neurosurgery will discuss study participation with potential adult subjects or parents of potential minor subjects for education regarding this research study. The investigational nature and objectives of the trial, the procedures and treatments involved and their attendant risks and discomforts, and potential alternative therapies will be carefully explained to the patient or the patient’s parents or guardian if the patient is a child, and a signed informed consent and assent will be obtained according to institutional guidelines . Those patients that turn 18 while on study will be re -consented using an adult consent form. 14. VOLUNTEER SCREEN ING PROCEDURES Diagnostic or laboratory studies performed exclusively to determine eligibility for this trial must only be done after obtaining written informed consent. Documentation of the informed consent for screening will be maintained in the patien t’s research chart. Studies or procedures that were performed for clinical indications (not exclusively to determine eligibility) may be used for baseline values even if the studies were done before informed consent was obtained. Re-MATC H Protocol Page 52 of 106 Version: 20180628 15. STUDY PROCEDURES/STUDY I NTERVENTIONS 15.1 Overview In this Phase II trial, 35 to 42 children and young adults with reMB/PNETs will be treated with DC + xALT therapy at the MTD (3x107 T cells/kg) determined from the Phase I trial in order to estimate the clinical efficacy of this treatment. Patients unable to undergo surgical resection, dependent on corticosteroid supplements above physiologic levels at time of first vaccine ( > 4 mg decadron per day), whose final pathology is not recurrent MB or PNET, unable to generate mRNA from resec ted tumor specimen, fail induction chemotherapy regimen due to tumor progression, or are unable to tolerate HDC after induction therapy will be replaced. If either DCs and/ or xALT do not meet release criteria or targeted dose then the patient may remain on study and receive the qualified product but will be replaced for the purposes of safety assessment. A study schema outlining the stages of this clinical protocol covering both Groups is provided in Section s 2.2, 2.3, and 2.4. 15.2 Chemotherapy for Group A 15.2.1 INDUCTION THERAPY During Induction therapy, surgery and anti -cancer drugs (chemotherapy) are used to remove and to kill as much tumor as possible. Also, peripheral blood stem cells (PBSCs) are collected during the Induction phase of therapy by leukapheresis as described below. Surgery : Maximal debulking surgery will be performed to minimize tumor burden and confirm diagnosis of recurrent tumor. All tumors will be confirmed as recurrent MB/PNET by a board- eligible/board -certified neuropathologist . Tumor tissue in excess of what is needed to confirm pathologic diagnosis will be transported under aseptic precautions to Dr. Mitchell’s laboratory for tumor RNA preparation. Tumor tissue may also be obtained through biopsy or CSF (cytology). Patients will undergo a non- mobilized leukapheresis prior to induction for harvest of peripheral blood mononuclear cells (PBMCs) for TTRNA -xALT and TTRNA -DC generation. The target PBMC count based on the desired dose of TTRNA -xALT and sufficient TTRNA -DCs for T cell expansion and in vivo vaccination will be collected. Approximately two weeks but no more than four weeks post -surgical resection , patients will continue induction treatment with 3 -4 cycles of chemotherapy at 28 -day intervals. Cycles 1 & 2 will consist of intravenous cyclophosphamide. Cycles 3 & 4 will consist of oral etoposide plus oral temozolomide (TMZ) . After each induction cycl e, patients will receive G -CSF in order to mobilize PBSCs for later stem cell support following high-dose chemotherapy. G -CSF will be given daily starting 24 hours following the last dose of chemotherapy and until completion of the leuka pheresis procedure. Peripheral blood stem cells (PBSC) will be collected after each induction cycle until the target CD34(+) PBSC yield needed for Consolidation (2x106 CD34+ cells per Kg at a minimum) is obtained. Absolute nucleated cell count collected will be adjusted as needed on a patient specific basis. The drugs will be given on the following schedule: Leukapheresis after each induction cycle until collection of a minimum 2x106 CD34+ cells/kg Cycle 1 & 2 Drug Dosage Route Days Given Cyclophosphamide 2g/m2/day IV over 1 hour 1, 2 Mesna 2g/m2/day IV 1, 2 Re-MATC H Protocol Page 53 of 106 Version: 20180628 Filgrastim 10mcg/kg/day SQ or IV 3 - 28* Cycle 3 & 4 Temozolomide 150mg/m2/day By mouth 1 - 5 Etoposide 30mg/m2/day By mouth 1 - 14 Upon recovery from the 3rd or 4th cycle of induction chemotherapy (ANC > 1000 cells/ µL), patients will undergo disease restaging and organ function evaluation. Patients dependent on steroid supplements above physiologic levels at time of Vaccine #1 (> 4 mg decadron per day), have radiographic or histologic evidence of progress ion will be replaced.