Patients with high-risk neuroblastoma after third-line chemotherapy. Patients with high-risk medulloblastoma/PNET after spinal irradiation. Patients with primary sarcomas after third or more line therapies, Patients with relapsed lymphomas after third line chemotherapy. Patients with relapsed neuroblastoma, medulloblastoma, lymphoma or sarcoma after previous autologous stem cell transplantation.