In a prospective single-arm study, decitabine plus DLI was applied as prophylaxis in 28 patients with high-risk hematological malignancies, defined as with at least one of the unfavorable gene mutations (FLT3- ITD, TP53, ASXL1, DNMT3A, or TET2) (AML, n = 23; MDS, n = 2; ALL, n = 3). Here, FLT3 is linked to acute myeloid leukemia.