Dexamethasone 12 mg/m2 (std/high risk) or 8 mg/m2 (low risk) PO daily (divided t.i.d.) for 5 days, Days 1-5. Doxorubicin 30 mg/m2 IV, Day 1. Vincristine 2 mg/m2 IV push (max. 2 mg), Day 1 (0.05 mg/kg for patients < 1 year of age or < 10kg in weight). MP (mercaptopurine) 50 mg/m2 PO daily for 7 days (std/high risk), Days 1-7, 75 mg/m2 PO daily for 7 days (low risk), Days 1-7. PEG-ASP (PEG-asparaginase) 2,500 vs. 3,500 units/m2 IV randomization, Day 1. Methotrexate 40 mg/m2 IV Day 1.