DISEASE CHARACTERISTICS: Diagnosis of one of the following: Acute myelogenous leukemia (M0-M7) M3 must have received tretinoin as part of induction or salvage chemotherapy No greater than 2 prior intensive induction regimens Acute lymphocytic leukemia (L1 or L2) in first or second relapse Circulating blasts in blood or greater than 5% blasts in bone marrow No greater than 2 prior intensive induction regimens Chronic myelogenous leukemia in myeloid or lymphoid blast crisis Initial diagnosis OR No greater than 2 prior intensive induction regimens Acute myelogenous leukemia secondary to prior myelodysplastic syndrome or prior cytotoxic therapy No greater than 2 prior intensive induction regimens Myelodysplastic syndrome (must be neutropenic (absolute neutrophil count less than 500/mm3) or platelet or red cell transfusion dependent) Refractory anemia with excess blasts (RAEB) OR RAEB in transformation OR Chronic myelomonocytic leukemia Relapse after greater than 3 months since prior autologous stem cell transplant allowed No relapse after allogeneic bone marrow transplant No active CNS leukemia