MECOM and acute myeloid leukemia: This fusion was considered biologically similar to other PRDM16 rearrangements known to occur in AML (16, 17) because: 1) the PRDM16 exons (exons 2–17) preserved in the fusion are the same as those in previously reported PRDM16 fusions; 2) overexpression of PRDM16 was observed in WTS; and 3) the global gene expression profile is compatible with the PRDM16/MECOM-r AML subtype (18) (Supplementary Figure S9).