MLN8237 to Treat Children With Relapsed/Refractory Solid Tumors

Inclusion Criteria: * Diagnosis: Patients must have had histologic verification of malignancy at original diagnosis or relapse except in patients with intrinsic brain stem tumors, optic pathway gliomas, or patients with pineal tumors and elevations of CSF or serum tumor markers including alpha-fetaprotein or beta-HCG. * Performance Level: Karnofsky \>/= 50% for patients \> 16 years of age and Lansky \>/= 50 for patients \</=16 years of age * Patients must have fully recovered from the acute toxic effects of all prior chemotherapy, immunotherapy, or radiotherapy prior to entering this study * Adequate Bone Marrow Function Defined as: a. For patients with solid tumors: * Peripheral absolute neutrophil count (ANC) \>/= 1000/microLiter * Platelet count \>/= 100,000/microLiter (transfusion independent, defined as not receiving platelet transfusions within a 7 day period prior to enrollment) * Hemoglobin \>/= 8.0 g/dL (may receive RBC transfusions) * Creatinine clearance or radioisotope GFR \>/= 70ml/min/1.73 m2 * Bilirubin (sum of conjugated + unconjugated) \</= 1.5 x upper limit of normal (ULN) for age, and * SGPT (ALT) \</= 5.0 x ULN for age (≤ 225 U/L). For the purpose of this study, the ULN for SGPT is 45 U/L. * Serum albumin \>/= 2 g/dL. Exclusion Criteria: * Pregnant or breast-feeding women will not be entered on this study * Growth factors that support platelet or white cell number or function must not have been administered within the 7 days prior to enrollment. * Patients receiving corticosteroids who have not been on a stable or decreasing dose of corticosteroid for the prior 7 days are not eligible. * Patients who are currently receiving another investigational drug are not eligible. * Patients who are currently receiving other anticancer agents, digoxin, cyclosporine, tacrolimus or sirolimus, use of daily benzodiazepines are not eligible * Patients who have an uncontrolled infection are not eligible.