Mitchell) and the Medical Monitor and compared with this table. If the expected accrual diversity is not met or if accrual overall is slower than anticipated (assessed every 3 months), we wi ll initiate a targeted recruitment program through techniques already established within our multi -institutional sites , including the placement of advertisements in newspapers or on radio stations to increase public awareness overall and specifically cater ing to the underrepresented population(s) and providing educational seminars for patients and staff at community institutions such as churches and medical clinics that preferentially serve the underrepresented population(s). The PRTBTC has a strong referr al network and we will Re-MATC H Protocol Page 51 of 106 Version: 20180628 also utilize resources such as the Pediatric Brain Tumor Consortium and the Pediatric Brain Tumor Foundation of the United States to increase publici ty and recruitment for this trial should accrual fall below expectation. 12. SAMPLE S IZE JUSTIFICATION Progression- free survival in Group A will be measured from the initiation of HDC for comparison to our historical experience of HDC + PBSCT in this patient population. The progression- free survival experience among patients with recurren t disease who initiated HDC after having previously received definitive radiotherapy is reported by Gururangan (2008). The 12- month PFS rate is 33% (95% confidence interval: 10%, 59%) with a two-year PFS of 0%. Due to the complexity and expense of adopt ive cellular therapy treatment, if the true PFS -12 associated with DC + xALT therapy is 33%, there would be limited interest in further investigation of this treatment regimen without significant modification to improve efficacy. However, if the true PFS -12 were 55% or greater, there would be interest in studying this treatment regimen within the context of larger confirmatory Phase II or III clinical trials. Therefore, the study is designed to differentiate between a PFS -12 rate of 33% (null hypothesis) and 55% (alternative hypothesis). With 35 patients enrolled in the Phase II trial, this assessment has 90% power assuming a type I error rate of 0.10. There is also 97% power to differentiate between PFS -12 rates of 33% and 60%. In Group B, progression- free survival will be measured from the time of proximal tumor recurrence before adoptive cellular therapy . Patients with progression prior to immunotherapy may remain on study as long as they continue to meet other eligibility requirements. Currently, no good historical benchmark exists for this patient population. The Group A benchmark described above will be used conservatively for patients in Group B given that they are generally considered to have poorer prognosis than Group A. Given this assumption, the sample size justification described above is also applicable to Group B.