More than 50% of infant, childhood and adolescent patients (<18 years old) with AML have abnormal karyotypes, which include aneuploidy (monosomy 5 and 7, trisomy 8 and 21) and such chromosomal rearrangements as t(9;11)/KMT2A/MLLT3, t(15;17)/PML/RARA, t(8;21)/RUNX1/RUNX1T1, and inv(16)/t(16;16)/CBFB/MYH11 (see Marcotte et al. [121] and other reports [127,192,193]). This evidence concerns the gene MLLT3 and acute myeloid leukemia.