Despite intensive studies on MLL-ENL, MLL-AF4, and MLL-AF9, there has been no report investigating the in vivo oncogenic potential of MLL-AF10 in human HSCs, even though MLL-AF10 is the second most common MLL rearrangement (13%) in pediatric MLL-rearranged AML [3]. This evidence concerns the gene KMT2A and acute myeloid leukemia.