Although significantly fewer than for pediatric ALL, backtracking studies have detected t(15;17)/PML/RARA and t(8;21)/RUNX1/RUNX1T1 fusion genes in neonatal blood spots or UCB of children or adolescents subsequently developing AML, indicating that these as a minimum can be initiated in utero [121,200,201,202,203]. The gene discussed is RUNX1T1; the disease is acute myeloid leukemia.