Patients will receive Decitabine until blast <5% is achieved, suitable HLA-matched donor or umbilical cord blood is available up to a maximum of 6 cycles. Patient who progress on therapy or are unable to find a donor by 6 cycles will be removed from protocol. The method, conditioning regimen and choice of donor will be determined based on patient's age and functional status, and transplant physician's discretion. The available regimens are standardized within the center