KLF5 and precursor B-cell acute lymphoblastic leukemia: Herein, we report that BCR-ABL1+ B-ALL has a strikingly reduced expression of KLF5, which is supported by the reported hypermethylation of the KLF5 promoter in patient-derived BCR-ABL1+ leukemic cells [19], suggesting that KLF5 may play preferentially a role as tumor suppressor in BCR-ABL1+ B-ALL.