IRF4 and precursor B-cell acute lymphoblastic leukemia: Furthermore, the oncomir microRNA-125b is up-regulated in several types of leukemias, including acute myeloid leukemia (AML) and B-ALL and is reported to inhibit IRF4 expression while inducing tumorigenesis in hematopoietic progenitor cells and myeloid and B cell neoplasms [26].