 - CNS therapy HR and VHR patients: Patients receive vincristine, mercaptopurine, dexamethasone, and TIT as in the SR group. Patients also receive dexrazoxane hydrochloride IV over 15 minutes followed by DOX IV over 15 minutes on day 1. HR patients also receive IV-PEG OR IM-EC as above beginning on day 1 and continuing for up to 30 weeks. VHR patients continue to receive IV-PEG OR IM-EC as per consolidation I treatment. Patients proceed to consolidation II after day 21. 