- Patients > 9 years old and pubertal and/or >15 year and less than or equal to 55 years, with aggressive leukemia (Acute Myelogenous Leukemia (AML), myelodysplastic syndromes (MDS) with high risk cytogenetics, Acute Lymphocytic Leukemia (ALL), CMML, certain CML) requiring HSCT will be enrolled at NCI.