RATIONALE: Studying samples of tissue from patients with cancer in the laboratory may help doctors learn more about cancer and the development of drug resistance in patients.

PURPOSE: This laboratory study is examining tissue samples from patients with acute myeloid leukemia to learn more about drug resistance in these patients.

OBJECTIVES:

• Ascertain whether assessments of P-glycoprotein (P-gp) status using the accumulation assay find greater than 10% positive specimens among 30 specimens (collected from patients with acute myeloid leukemia enrolled on clinical trial ECOG-E3999) found to be negative using only the efflux assay.

OUTLINE: This is a multicenter study.

Cryopreserved bone marrow specimens are examined for P-glycoprotein (P-gp) by the accumulation assay and the efflux assay using DiOC_2 dye. Flow cytometry is used for measuring activity in both assays.

PROJECTED ACCRUAL: A total of 40 specimens will be accrued for this study.

DISEASE CHARACTERISTICS:

• Cryopreserved bone marrow specimens collected from patients with acute myeloid leukemia enrolled on clinical trial ECOG-E3999 meeting the following criteria:

  • Appreciable levels of either CD34+ OR CD117+ blasts
  • Appreciable staining with anti-P-gp antibodies

• 30 specimens must exhibit low to moderate dye loading for the Rh123 efflux assay

• 10 specimens must exhibit positive Rh123 efflux activities

PATIENT CHARACTERISTICS:

• Not specified

PRIOR CONCURRENT THERAPY:

• Not specified

Samples submitted for research from patients participating in E3999