KMT2A and acute lymphoblastic leukemia: A study by Garrido et al. used the FISH method to analyze 39 adult B-ALL patients negative for the BCR-ABL1 and KMT2A gene rearrangements and identified 3/39 (7.7%) cases with ABL-class fusions (ABL1 n = 2; CSF1R n = 1) [29].