KMT2A and leukemia: Finally, to assess whether mAb2 has the potential to target human AML patient cells in vivo, we performed flow cytometry analysis to examine the csNPM1 levels in a patient-derived xenograft (PDX) model driven by an MLL-rearrangment (MLL-R), which are seen in 40% of pediatric leukemia and 5-12% of adult AML42.