Heterogeneous cytogenetic subgroups and outcomes in childhood acute megakaryoblastic leukemia: a retrospective international study

Comprehensive clinical studies of patients with acute megakaryoblastic leukemia (AMKL) are lacking. We performed an international retrospective study on 490 patients (age 50 chromosomes (n=44, 11.8%). Chromosome gain occurred in 195 of 372 (52.4%) patients: +21 (n = 106, 28.5%), +19 (n = 93, 25.0%), +8 (n = 77, 20.7%). Losses occurred in 65 patients (17.5%): -7 (n = 13, 3.5%). Common structural chromosomal aberrations were t(1; 22)(p13; q13) (n = 51, 13.7%) and 11q23 rearrangements (n = 38, 10.2%); t(9; 11)(p22; q23) occurred in 21 patients. On the basis of frequency and prognosis, AMKL can be classified to 3 risk groups: good risk-7p abnormalities; poor risk-normal karyotypes, -7, 9p abnormalities including t(9;11)(p22;q23)/MLL-MLLT3, -13/13q-, and -15; and intermediate risk-others including t(1;22)(p13;q13)/OTT-MAL (RBM15-MKL1) and 11q23/MLL except t(9;11). Risk-based innovative therapy is needed to improve patient outcomes