OBJECTIVES: I. Compare the outcomes in children with higher risk acute lymphocytic leukemia (ALL) treated with postinduction chemotherapy based on marrow response on day 7 of induction therapy: for patients with rapid early response (M1/M2), standard vs intensified consolidation chemotherapy and standard vs prolonged duration of intensification chemotherapy; for patients with slow early response, addition of doxorubicin vs idarubicin and cyclophosphamide to intensification chemotherapy. II. Decrease the incidence of avascular necrosis by alternating dexamethasone dosing in patients undergoing 2 courses of delayed intensification. III. Assess the impact of day 7 marrow status on outcome in these patients. IV. Determine prognosis more precisely by supplementing presenting clinical features, immunophenotype, ploidy, cytogenetics, and early marrow response with BAX/BCL-2 ratios, pattern of tyrosine kinase activation, leukemic burden following induction and intensification therapy, and development of high antibody titer to E. coli asparaginase. V. Correlate the traditional prognostic factors of day 7 marrow response, immunophenotype, ploidy, cytogenetics, and early marrow response with BAX/BCL-2 ratios.