In MLL1-rearranged AML, the N-terminus of the MLL1 gene is fused to the C-terminus of any of over 80 fusion partners, including AF4, AF9, ENL, and ELL, which are part of and recruit the super elongation complex (SEC) (including AFF1/4 and pTEFb) and DOT1L to induce H3K4Me3 and H3K79Me2 marks on active chromatin [5, 10, 12, 13]. This evidence concerns the gene AFF1 and acute myeloid leukemia.