Immunodeficient NSG mice (n = 19) were xenotransplanted with our MLL-rearranged ALL luciferase reporter cell line SEM-SLIEW and equally allocated over vehicle (n = 10) and irinotecan (n = 9; 40 mg/kg) treatment groups, ensuring comparable leukemia burden before treatment (Supplementary Figure S3A). Here, KMT2A is linked to acute lymphoblastic leukemia.