- Determine whether autologous transplantation of mobilized CD34+ peripheral blood stem cells (PBSC) can provide complete hematologic reconstitution after myeloablative chemotherapy comprising etoposide (VP-16) and carboplatin (CBDCA) in patients with metastatic or recurrent rhabdomyosarcoma, neuroblastoma, Ewing's sarcoma/primitive neuroectodermal tumor, germ cell tumors, childhood brain tumors, or hepatoblastoma.