Incorrect DOT1L recruitment as a result of chimeric gene fusions between DOT1L-interacting proteins AF10/ENL and the histone H4 methyltransferase mixed lineage leukemia (MLL) lead to aberrant H3K79 methylation patterns and increased transcription of oncogenes that cause leukemia (35, 40, 41), further supporting a role of DOT1B in transcription. Here, DOT1L is linked to leukemia.