AFF1 and acute lymphoblastic leukemia: Infant ALL patients (n = 987) displayed the following rearrangements: AFF1 (n = 477; 48,3%), MLLT1 (n = 234; 24%) MLLT3 (n = 157; 16%), MLLT10 (n = 59; 6%), EPS15 (n = 22; 2,2%) AFDN (n = 3; 0,3%), and 15 other KMT2A rearrangements.