Studying Body Mass Index in Younger Patients Who Are Receiving Treatment for High-Risk Acute Lymphoblastic Leukemia

Inclusion Criteria:

* Patients must be newly diagnosed with acute lymphoblastic leukemia and the intended induction treatment must contain prednisone/prednisolone, vincristine and daunorubicin in the doses and schedule as per the current COG AALL0232 protocol; prior registration onto a COG protocol is not required
* Patients must be able to take either prednisone/prednisolone reliably by mouth on day 1 or 8 of induction (depending on sampling schedule chosen); patients who are being sampled on Induction day 8 and who have received intravenous corticosteroid therapy in the first week of induction must have received a minimum of six oral prednisone/prednisolone doses prior to the morning prednisone/prednisolone dose on induction day 8

Exclusion Criteria:

* Serum transaminase concentrations \>= 5 X ULN for age
* Total serum bilirubin (conjugated + unconjugated) \>= 1.5 mg/dl (\>= 26 micromol/L)
* Serum creatinine \> 1.5 X ULN for age
* With the exception of prednisone/prednisolone, receipt of medications or food known or with the potential to alter the pharmacokinetics of the drugs under study within 14 days of diagnosis and throughout the period of pharmacokinetic sampling; such agents include but are not limited to: grapefruit, tangelos or the juice of these fruits; St. Johns wort; anticonvulsants: carbamazepine, oxcarbazepine, phenytoin, phenobarbital, primidone; azole antifungal agents: ketoconazole, fluconazole, itraconazole, voriconazole; macrolide antibiotics: erythromycin, clarithromycin; isoniazid; rifampin; verapamil; and diltiazem
* Presence of known malabsorption syndrome
* Females with known pregnancy (pregnancy test must be negative to be eligible)