Patients receiving corticosteroids are not eligible; patients must have been off corticosteroids for 7 days prior to start of chemotherapy Corticosteroids: patients who are receiving dexamethasone must be on a stable or decreasing dose for at least 1 week prior to registration Patients must be maintained on a stable corticosteroid regimen (no increase for 5 days) prior to the start of treatment Patients receiving corticosteroids are eligible for this trial Patients receiving corticosteroids who have not been on a stable or decreasing dose of corticosteroid for at least 7 days prior to enrollment are not eligible Corticosteroids: patients who are receiving dexamethasone or other corticosteroids must be on a stable or decreasing dose for at least 1 week prior to enrollment; it is recommended that patients be off all steroid therapy or receive the least dose that will control their neurologic symptoms Patients receiving corticosteroids who have not been on a stable or decreasing dose of corticosteroid for at least 7 days prior to enrollment are not eligible Solid tumor patients must be off corticosteroids prior to registration; if GBM patient is receiving corticosteroids, patient must be on a stable or decreasing dose of corticosteroids for at least 5 days prior to baseline magnetic resonance imaging (MRI) or computed tomography (CT); if steroids are added or the steroids dose is increased between the date of the screening MRI or CT and the start of treatment, a new baseline MRI or CT is required Patients receiving corticosteroids who have not been on a stable or decreasing dose of corticosteroid for at least 7 days prior to enrollment are not eligible Must have been taking a stable dose of corticosteroids for symptom management for at least 1 week before baseline MRI If patient is on corticosteroids, the dose must be stable or decreasing for at least 5 days prior to enrollment Corticosteroid dose must be stable or decreasing for at least 5 days prior to the baseline MRI scan Patients must be maintained on a stable corticosteroid regimen (no increase for 5 days) prior to the baseline MRI Patients must be able to undergo MRI of the brain with gadolinium; patients must be maintained on a stable or decreasing dose of corticosteroid regimen (no increase for 5 days) prior to this baseline MRI