This study is for patients that have been diagnosed with Newly Diagnosed Diffuse Anaplastic Wilms Tumors (DAWT) and Relapsed Favorable Histology Wilms Tumors (FHWT). The treatment involves cancer fighting medicine called chemotherapy plus radiation therapy and/or surgery. Participants can expect to be on this study for up to 10 months and be followed by the treatment team for up to 5 years.

This study is for patients that have been diagnosed metastatic germ cell tumors. This study will compare the standard chemotherapy regimen with an accelerated chemotherapy regimen using the same drugs to see if the accelerated chemotherapy regimen is beneficial but not more toxic than the standard chemotherapy regimen. The accelerated chemotherapy is experimental. Participants can expect to be on study for about 3 months and continue to be followed for up to 5 years.

This study is for patients that have been diagnosed with Epstein-Barr Virus associated Post-Transplant Lymphoproliferative Disorder (EBV-PTLD). The investigational drug in this study is tabelecleucel. Tabelecleucel is a product containing special immune allogeneic cells, called EBV-Cytotoxic T Lymphocytes (EBV-CTLs), that are made in the laboratory starting with cells from a healthy person who is immune to EBV. The purpose of this study is to test how well tabelecleucel works to treat EBV-PTLD following SOT in patients who have not responded to rituximab or rituximab plus chemotherapy treatment and to see what side effects happen. Your participation will help us to understand more about tabelecleucel. In the first 12-month period, participants will be asked to come to the clinic for an estimated 11 to 19 study visits and a minimum of 2 scans, depending on the number of cycles of treatment they are given. After treatment is done, participants will enter into the follow-up phase, and will continue to come into the clinic for scheduled check-ups for up to 24 months after the first dose of tabelecleucel was given. Participant information on the status of their disease and any new treatment will be collected for up to an additional 3 years. Participants can expect to be in this study for up to five years total.

This study is for patients that have been diagnosed with multisystem Langerhans cell histiocytosis (LCH). The purpose of this study is to find out if prolonging the treatment and adding a drug called 6-mercaptopurine will be beneficial. Other goals include fining out if these changes will result in fewer patients having relapse of their LCH, and fewer patients having long term disease related problems. Participants can expect to be in this study for up to 24 months and will be followed on this study fir at least 5 years.

This study is for patients that have been diagnosed with Germ Cell Tumors. The purpose of this study is to evaluate whether a strategy of complete surgical resection followed by surveillance can maintain an overall survival rate of at least 95.7% at two years for pediatric, adolescent and adult patients (ages 0- 50 years) with Stage I (low risk) malignant germ cell tumors, and at least 98% for patients with ovarian pure immature teratoma. The drugs used in this study are carboplatin and cisplatin. Participants will be followed for up to 10 years.

The overall goal of this study is to find out what effects, good and/or bad, a low
dose and a high dose of lenalidomide have on children, adolescents and young
adults with recurrent (has come back after being treated), refractory (has not gone
away with previous treatment), or progressive (is not responding to previous
treatments) Juvenile Pilocytic Astrocytomas (JPA) and Optic Pathway Gliomas
(OPG).

the United States, it is standard treatment for patients with high-risk neuroblastoma (NBL) to receive the drugs carboplatin, etoposide and melphalan (CEM) as the preparative regimen in Consolidation therapy prior to Autologous Stem Cell Transplant (ASCT). BuMel Consolidation therapy has recently been studied in patients with high-risk NBL in some European countries. The findings from those studies indicate that the use of BuMel prior to ASCT may be linked to an increase in the survival rate for patients when compared to CEM. Those studies also indicate that the chance of the disease coming back (a relapse) may be lower among the patients who received BuMel Consolidation therapy. In North America the BuMel combination is considered experimental. In this study, researchers want to find out if a combination of busulfan and melphalan (BuMel) can be given as Consolidation therapy prior to ASCT for subjects with newly diagnosed high-risk NBL. The main goal of this study is to find out what effects, good and/or bad, a BuMel preparative regimen given before ASCT has on people with newly diagnosed high-risk NBL.

Ependymoma is a type of rare childhood cancer that occurs in the brain and spinal cord. Survival statistics are generally disappointing with a 5-year survival of 50-64%. The standard of care for ependymoma is maximal surgical resection followed by radiation therapy directed at the primary site of disease.

Radiation therapy is associated with immediate and long-term toxicities in children, especially young children. For this reason, it has been the practice of some doctors not to give radiation therapy to children with ependymoma when the tumor has been completely surgically removed. The investigators who designed this study have created strict measures to choose those who will not receive additional treatment after surgery and careful follow-up to minimize the risks to those who are assigned to observation only.

To collect information about the patient's leukemia and to seek the optimal treatment for children with ALL based on the individual level of risk of the cancer coming back after treatment. The risk groups are defined as a result of recent research conducted by the Children's Oncology Group (COG). We would like to learn if the use of an experimental intrathecal therapy (ITT), which has been given to many people with ALL and has been well tolerated, would be better at preventing relapse in the central nervous system and improve disease outcomes in children with High Risk ALL.

The Center for International Blood and Marrow Transplant Research (CIBMTR ) keeps a research database. It uses this database to collect and study the medical data for patients that have received Hematopoietic Cell Transplantation, Other Cellular Therapies and Marrow Toxic Injuries. It also collects and studies data from donors who give bone marrow or peripheral blood stem cells (PBSCs). These therapies are used to treat cancer and other diseases. The purpose of this study is to add more data to the database. Participants will have medical data (data about their disease, transplant or cellular therapy) collected before and after transplant cellular therapy, and once a year afterwards for life.