This phase II trial studies the treatment response for patients with acute graft-versus-host disease (GVHD). GVHD occurs when donor immune cells attack the healthy tissue of a bone marrow or stem cell transplant patient. The standard treatment for GVHD is to lower the activity of the donor cells by using steroid medications such as prednisone. But steroid treatment may cause many complications and the risk of these complications increases with higher doses of steroids and longer treatment. It is important to find ways to decrease the steroid treatment in patients who do not need long courses. Researchers are doing this study to find out how many subjects respond well to lower steroid dosing based on a blood test (GVHD biomarker) and if they develop fewer complications.

This study evaluates immunologic response following COVID-19 vaccination in children, adolescents, and young adults with cancer. Vaccines work by stimulating the bodys immune cells to respond against a specific disease. The immune response produces protection from that disease. Effects from cancer and from treatments for cancer can reduce the bodys natural disease fighting ability (called immunity). Factors such as vaccine type, timing of vaccine dosing related to treatment for cancer and number of vaccine doses or boosts (extra vaccine shots) may strengthen or diminish the bodys protective immune response. This study may help researchers learn more about how the bodys immune system responds to the COVID-19 vaccine when the vaccination is given during or after cancer treatment.

This randomized clinical phase III trial studies how well web-based physical activity intervention works in improving long term health in children and adolescents with cancer. Regular physical activity after receiving treatment for cancer may help to maintain a healthy weight and improve energy levels and overall health.

This study aims to use clinical and biological characteristics of acute leukemias to screen for patient eligibility for available pediatric leukemia sub-trials. Testing bone marrow and blood from patients with leukemia that has come back after treatment or is difficult to treat may provide information about the patient's leukemia that is important when deciding how to best treat it, and may help doctors find better ways to diagnose and treat leukemia in children, adolescents, and young adults.

Difluoromethylornithine (DFMO) will be used in an open label, single agent, multicenter,
study for patients with neuroblastoma in remission. In this study subjects will receive 730
Days of oral difluoromethylornithine (DFMO) at a dose of 750 mg/m2 250 mg/m2 BID (strata 1,
2, 3, and 4) OR 2500 mg/m2 BID (stratum 1B) on each day of study. This study will focus on
the use of DFMO in high risk neuroblastoma patients that are in remission as a strategy to
prevent recurrence.

This phase II trial investigates evolutionary inspired therapy in treating fusion positive rhabdomyosarcoma that is newly diagnosed and has spread to other places in the body (metastatic). Chemotherapy drugs, such as vinorelbine, vincristine sulfate, and actinomycin D, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Cyclophosphamide is used to decrease the body's immune response and may inhibit DNA replication and initiate cell death. This study is being done to determine which of 4 different therapeutic treatments will have the best chance of the disease not worsening or coming back.

The LCH-IV is an international, multicenter, prospective clinical study for pediatric
Langerhans Cell Histiocytosis LCH (age < 18 years).

Rhabdomyosarcoma is a type of cancer that occurs in the soft tissues in the body. This phase III trial aims to maintain excellent outcomes in patients with very low risk rhabdomyosarcoma (VLR-RMS) while decreasing the burden of therapy using treatment with 24 weeks of vincristine and dactinomycin (VA) and examines the use of centralized molecular risk stratification in the treatment of rhabdomyosarcoma. Another aim of the study it to find out how well patients with low risk rhabdomyosarcoma (LR-RMS) respond to standard chemotherapy when patients with VLR-RMS and patients who have rhabdomyosarcoma with DNA mutations get separate treatment. Finally, this study examines the effect of therapy intensification in patients who have RMS cancer with DNA mutations to see if their outcomes can be improved.

This phase II trial studies the best approach to combine chemotherapy and radiation therapy (RT) based on the patients response to induction chemotherapy in patients with non-germinomatous germ cell tumors (NGGCT) that have not spread to other parts of the brain or body (localized). This study has 2 goals: 1) optimizing radiation for patients who respond well to induction chemotherapy to diminish spinal cord relapses, 2) utilizing higher dose chemotherapy followed by conventional RT in patients who did not respond to induction chemotherapy. Chemotherapy drugs, such as carboplatin, etoposide, ifosfamide, and thiotepa, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Radiation therapy uses high energy x-rays or high-energy protons to kill tumor cells and shrink tumors. Studies have shown that patients with newly-diagnosed localized NGGCT, whose disease responds well to chemotherapy before receiving radiation therapy, are more likely to be free of the disease for a longer time than are patients for whom the chemotherapy does not efficiently eliminate or reduce the size of the tumor. The purpose of this study is to see how well the tumors respond to induction chemotherapy to decide what treatment to give next. Some patients will be given RT to the spine and a portion of the brain. Others will be given high dose chemotherapy and a stem cell transplant before RT to the whole brain and spine. Giving treatment based on the response to induction chemotherapy may lower the side effects of radiation in some patients and adjust the therapy to a more efficient one for other patients with localized NGGCT.