AFF1 and acute myeloid leukemia: To functionally characterize the role of H3K79me2 or DOT1L in mediating SE sites in AML, we conducted several functional assays in two selected MLL-r AML cell lines, MV-4-11 (MLL-AF4) and MOLM14 (MLL-AF9), and a lymphoblastoid cell line, GM12878.