BCS1L and acute lymphoblastic leukemia: Adult ALL patients (n = 647) displayed the following rearrangements: AFF1 (n = 535; 82.7%), MLLT1 (n = 66; 10.2%), AFDN (n = 10; 1.5%), MLLT3 (n = 8; 1.2%), EPS15 (n = 4; 0.6%), MLLT10 (n = 3; 0.5%), ELL (n = 1; 0.1%), KMT2A-PTD (n = 1; 0.1%) and 14 other KMT2A rearrangements.