A handful of translocation partners, namely AFF1/AF4, MLLT3/AF9, MLLT1/ENL, MLLT10/AF10, and MLLT4/AF6, were found to be involved in 70–95% of the MLL translocations, with some differences in frequencies of individual partners in ALL vs. AML, infant vs. adult, and de novo vs. therapy-induced leukemia (Meyer et al., 2009, 2013; De Braekeleer et al., 2011; Cerveira et al., 2012; Emerenciano et al., 2013). This evidence concerns the gene MLLT1 and leukemia.