MECOM and acute lymphoblastic leukemia: Rearrangements of the 3q26 region, which encompasses the MECOM (MDS–EVI1 complex) gene that encodes EVI1 transcripts and that are commonly associated with EVI1 overexpression in adult AML, rarely occur in childhood ALL or AML.2, 4 However, when EVI1 is expressed in childhood AML it seems to be predominate in MLL-rearranged cases,4, 5 which may then confer an adverse prognosis, as illustrated by the correlation with the t(6;11) subtype,4 and with complex karyotype cases.