Survival curves for patients with 11q23/MLL-rearranged pediatric AML grouped on the basis of different translocation partners. (A) Event-free survival curves. (B) Overall survival curves. Assignment to 11q23-rearranged subgroups was based on translocation partners, as identified after central review of karyotyping. Some patients were assigned to 11q23 subgroups based on RT-PCR results only. If an MLL rearrangement was determined by FISH and the translocation partner was unknown, the patient was included in the “11q23/MLL-other” group. At least 10 patients had to be included to create a subgroup; otherwise, the cases were allocated to the 11q23/MLL-other group. Patients with a t(1;11)(q21;q23) showed independent favorable outcome with overall survival at 5 years of 100% ± 0%, and an event-free survival of 92% ± 5%. Several rearrangements were identified as predictors of poor clinical outcome, including t(6;11)(q27;q23), t(10;11)(p11.2;q23), t(4;11)(q21;q23), and t(10;11)(p12;q23).