KMT2A and leukemia: 11q23 is frequently rearranged or amplified in hematological malignancies due to the presence of the mixed-lineage leukemia gene (MLL, also termed KMT2A for lysine [K]-specific methyltransferase 2A), whose alterations represent one of the most common recurring oncogenic events in leukemia (Greaves and Wiemels, 2003, Yunis et al., 1989, Zeisig et al., 2012).