Molecularly, inv(3)/t(3;3) AML is characterized by the aberrant juxtaposition of the oncogene ecotropic viral integration site 1 (EVI1), with regulatory elements of ribophorin 1 (RPN1), resulting in overexpression of EVI1 (Buonamici et al., 2003). Here, MECOM is linked to acute myeloid leukemia.