Evaluation on the BCR-ABL positive K562 (CML) and FLT3-ITD positive MV-4-11 (AML) human cell lines revealed effective suppression of STAT5 phosphorylation and downregulation of target genes such as Cyclin D1, Cyclin D2, C-MYC and MCL-1. The gene discussed is STAT5B; the disease is acute myeloid leukemia.