Acute lymphocytic leukemia gene 1 fused from chromosome 9 (AF9), also known as mixed lineage leukemia translocated to chromosome 3 homolog (Mllt3) is frequently found in balanced translocations with the mixed lineage leukemia gene (MLL), a trithorax homolog, in acute myeloid leukemia cells. This evidence concerns the gene KMT2A and acute myeloid leukemia.