U2AF1 and acute myeloid leukemia: Another mechanism responsible for decreased EZH2 levels in AML is the 7q chromosomal deletion (−7), since EZH2 gene is located on this chromosome arm and these patients are often resistant to chemotherapy and characterized by a poor prognosis [84,156], Finally, splicing alteration due to mutations in genes involved in the splicing machinery, including SRSF2 and U2AF1 (near 10% of AML patients) decreases EZH2 transcript [155,157].