RATIONALE: Diagnostic procedures may improve the ability to detect residual disease.

PURPOSE: Clinical trial to detect the presence of residual disease in children who are receiving therapy for acute myeloid leukemia or myelodysplastic syndrome.

OBJECTIVES: I. Determine the frequency and prognostic significance of persistent abnormal cells with an aberrant phenotype detected by multidimensional flow cytometry (MDF) in bone marrow samples from children who have achieved clinical remission after receiving treatment for acute myeloid leukemia or myelodysplastic syndrome. II. Compare the frequency of persistent abnormal cells obtained by MDF with that of polymerase chain reaction (PCR), morphologic, and cytogenetic analyses of these patient samples. III. Determine the frequency and prognostic significance of persistent abnormal cells with a leukemia-specific molecular marker detected by PCR in samples from these patients.

OUTLINE: Patients have bone marrow samples collected during the course of therapy on the CCG 2961 acute myeloid leukemia treatment protocol. These samples are collected: 1. At the time of diagnosis 2. At the end of induction (within a week of day 35) 3. At the end of consolidation (before bone marrow transplant or Capizzi 2) 4. Before and after interleukin-2 (IL-2) therapy, if applicable 5. At the end of therapy (after transplant with evidence of engraftment for autologous bone marrow transplant patients; after course 2 of intensification for chemotherapy patients; and after IL-2 day 21 for IL-2 patients) 6. At relapse, if applicable. The presence of minimal residual disease in bone marrow is assessed using multidimensional flow cytometry and PCR.

PROJECTED ACCRUAL: A total of 400 patients will be accrued for this study.

DISEASE CHARACTERISTICS: Acute myeloid leukemia (AML) or myelodysplastic syndrome and enrolled on the CCG 2961 AML treatment protocol Must have one of the following cytogenetic abnormalities t(8;21) inv(16) abnormality of 11q23 OR All patients being enrolled for interleukin-2 therapy or standard care can be enrolled at the time of randomization

PATIENT CHARACTERISTICS: Age: Children Performance status: Specified on the CCG 2961 AML treatment protocol Life expectancy: Specified on the CCG 2961 AML treatment protocol Hematopoietic: Specified on the CCG 2961 AML treatment protocol Hepatic: Specified on the CCG 2961 AML treatment protocol Renal: Specified on the CCG 2961 AML treatment protocol

PRIOR CONCURRENT THERAPY: Specified on the CCG 2961 AML treatment protocols

Patients with acute myeloid leukemia or myelodysplastic syndrome (MDS) enrolled on the CCG 2961 AML treatment protocol.