AFF1 and acute myeloid leukemia: It has been shown that during lineage switch, KMT2A-AFF1 activates a series of target genes that are different from other KMT2Ar AML target genes at primary diagnosis.52 The target genes include many, such as SRGN and LYST that are involved in the production and secretion of hemopoietic granules and are normally expressed in granulocytes, particularly in neutrophils.