- Subjects with histologically confirmed CNS embryonal tumor (primitive neuroectodermal tumor [PNET], medulloblastoma, atypical teratoid rhabdoid tumor [ATRT], medulloepithelioma, pineoblastoma or ependymoblastoma), or germ cell tumor, are eligible; tumors must be relapsed or refractory to first-line therapy; diagnosis will be made on the basis of computed tomography (CT)-assisted or stereotactic biopsy, open biopsy, surgical resection, cerebrospinal fluid (CSF) cytology, or elevated tumor markers