MLLT1 and acute myeloid leukemia: In pediatric and adult acute myeloid leukemia (AML), the most frequent fusion partners are represented by MLLT3/AF9 (9p22), MLLT10/AF10 (10p12), ELL (19p13.1), MLLT4/AF6 (6q27) and MLLT1/ENL (19p13.3) (4), however, t(11;22)(q23;q11) is rare.