MECOM and myelodysplastic syndrome: However, approximately 10% of acute myeloid leukemia (AML) patients display abnormally high expression of the EVI1 transcript, but not the MDS1-EVI1 mRNA.24–27 Elevated EVI1 expression can be a result of 3q rearrangements, which comprise a high-risk AML entity as defined by the World Health Organization (WHO),28 but can also occur outside the context of such translocations, often in co-occurrence with mixed-lineage leukemia (MLL) rearrangements or chromosome 7 deletions.26 In Fanconi anemia patients suffering from MDS or AML, approximately every second patient shows EVI1 overexpression.