KMT2D and chronic myelogenous leukemia, BCR-ABL1 positive: In the present study, we demonstrate that KMT2D p. (Arg191Trp) was acquired in an imatinib-resistant CML cell line and its introduction into treatment-naïve K-562 cells displayed similar effects as siRNA-mediated KMT2D downregulation impairing the response to imatinib.