MLLT1 and acute lymphoblastic leukemia: Approximately 80% of the cases of infant ALL are characterized by chromosomal translocations involving the Lysine Methyltransferase 2A (KMT2A) gene in chromosome 11q23, in which the N-terminus of KMT2A fuses with the C-terminus of one of its translocation partner genes, such as AFF1 (AF4; in ~49% of cases), MLLT1 (ENL; ~22%) or MLLT3 (AF9; ~16%) [4].