The CBFA2T3 (a.k.a. ETO2 or MTG16) gene on the long arm of chromosome 16, encoding a transcriptional co-repressor, is targeted by two recurrent AML-associated chromosomal rearrangements, the t(16;21)(q24;q22) and the cytogenetically silent inv(16) (p13q24) leading to expression of RUNX1–CBFA2T3 and CBFA2T3–GLIS2 fusions, respectively. The gene discussed is RUNX1; the disease is acute myeloid leukemia.