Of over 80 different translocation partner genes, the translocation t (9; 11) (p22; q23) leading to the leukemogenic fusion gene MLL-AF9 is a frequent translocation in infant acute myeloid leukemia (∼50%) and especially associated with infant acute monocytic leukemia with MLL translocation (AML-FAB-M5, ∼70%) [58–61]. This evidence concerns the gene MLLT3 and acute monocytic leukemia.