RATIONALE: Radiation therapy uses high-energy x-rays to kill tumor cells. Drugs used in chemotherapy, such as arsenic trioxide and temozolomide, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Arsenic trioxide and temozolomide may also make tumor cells more sensitive to radiation therapy. Giving radiation therapy together with combination chemotherapy may kill more tumor cells. PURPOSE: This phase I trial is studying the side effects and best dose of arsenic trioxide when given together with temozolomide and radiation therapy in treating patients with newly diagnosed high-grade glioma.

RATIONALE: Monoclonal antibodies, such as bevacizumab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Bevacizumab may also stop the growth of tumor cells by blocking blood flow to the tumor. Erlotinib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Giving bevacizumab together with erlotinib may kill more tumor cells. PURPOSE: This phase II trial is studying how well giving bevacizumab together with erlotinib works after radiation therapy and temozolomide in treating patients with newly diagnosed glioblastoma multiforme or gliosarcoma.

RATIONALE: Sodium thiosulfate may reduce or prevent hearing loss in young patients receiving cisplatin for cancer. It is not yet known whether sodium thiosulfate is more effective than no additional treatment in preventing hearing loss. PURPOSE: This randomized phase III trial is studying sodium thiosulfate to see how well it works compared with no additional treatment in preventing hearing loss in young patients receiving cisplatin for newly diagnosed germ cell tumor, hepatoblastoma, medulloblastoma, neuroblastoma, or osteosarcoma.

RATIONALE: Sunitinib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth and by blocking blood flow to the tumor. PURPOSE: This phase II trial is studying how well sunitinib works in treating patients with recurrent malignant glioma.

RATIONALE: Gathering health information about patients with neurofibromatosis type 1 over time may help doctors learn more about the disease. PURPOSE: This clinical trial is studying changes over time in patients with neurofibromatosis type 1 and their healthy siblings.

RATIONALE: Gathering information about how young patients with ependymoma respond to standard combination chemotherapy and learning about the long-term effects of this treatment may help doctors plan better treatment. PURPOSE: This phase III trial is observing young patients with ependymoma undergoing standard combination chemotherapy.

RATIONALE: Cilengitide may stop the growth of tumor cells by blocking blood flow to the tumor. PURPOSE: This phase II trial is studying how well cilengitide works in treating younger patients with recurrent or progressive high-grade glioma that has not responded to standard therapy.

RATIONALE: Giving chemotherapy and radiation therapy before a peripheral stem cell transplant stops the growth of cancer cells by stopping them from dividing or killing them. Giving colony-stimulating factors, such as G-CSF, and certain chemotherapy drugs, helps stem cells move from the bone marrow to the blood so they can be collected and stored. Chemotherapy or radiation therapy is then given to prepare the bone marrow for the stem cell transplant. The stem cells are then returned to the patient to replace the blood-forming cells that were destroyed by the chemotherapy and radiation therapy. PURPOSE: This phase I trial is studying the best dose of temozolomide when given together with radiation therapy, carmustine, O6-benzylguanine, and an autologous stem cell transplant in treating patients with newly diagnosed glioblastoma multiforme or gliosarcoma.

RATIONALE: Tandutinib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Monoclonal antibodies, such as bevacizumab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Bevacizumab may also stop the growth of tumor cells by blocking blood flow to the tumor. Giving tandutinib together with bevacizumab may kill more tumor cells. PURPOSE: This phase II trial is studying the side effects of giving tandutinib together with bevacizumab and to see how well it works in treating patients with recurrent high-grade glioma.

RATIONALE: Cediranib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth and by blocking blood flow to the tumor. Drugs used in chemotherapy, such as temozolomide, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Radiation therapy uses high-energy x-rays to kill tumor cells. Giving cediranib together with temozolomide and radiation therapy may kill more tumor cells. PURPOSE: This phase I/II trial is studying the side effects and best dose of cediranib to see how well it works when given together with temozolomide and radiation therapy in treating patients with newly diagnosed glioblastoma.