RATIONALE: Studying samples of blood, tissue, and bone marrow from patients with cancer in the laboratory may help doctors learn about changes that occur in RNA and identify biomarkers related to cancer.

PURPOSE: This research trial studies RNA samples from patients with Down syndrome and acute myeloid leukemia or other transient myeloproliferative disorder.

OBJECTIVES:

• To compare miRNA expression in distinctive diagnostic groups: transient myeloproliferative disorder (TMD), Down syndrome (DS) acute megakaryocytic leukemia (AMkL), non-DS AMkL, and in remission DS samples (representing germline, non-malignant samples).

OUTLINE: Archived RNA samples are analyzed for mature micro (mi)RNA expression by real-time RT-PCR. Results are then compared with miRNA expression of non-Down syndrome patients with acute megakaryocytic leukemia.

DISEASE CHARACTERISTICS:

• Patients with Down syndrome (DS) diagnosed with acute myeloid leukemia or transient myeloproliferative disorder
• Clinical samples obtained from patients enrolled on the COG AAML0431 and COG AAML08B1

PATIENT CHARACTERISTICS:

• Previously consented to biologic studies

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics

Patients with Down syndrome (DS) diagnosed with acute myeloid leukemia or transient myeloproliferative disorder.