 I. Determine the toxicity of the addition of rituximab to induction chemotherapy comprising vincristine, methylprednisolone, methotrexate, leucovorin calcium, cyclophosphamide, and doxorubicin COPADM COMRAP and to consolidation chemotherapy in children with newly diagnosed FAB prognostic group B or group C leukemia or lymphoma treated with LMBFAB therapy. 