Surveys of copy number alterations in adult and pediatric AML identified focal amplifications of the 8q24.21 region in 3%–4% of cases,290,291 which were later shown to involve a hematopoietic SE 1.7 Mb downstream of MYC.289 Focal amplification of a region 730 kb downstream of BCL11B causes the generation of a hyperactive enhancer driving overexpression of this gene in a subgroup of lineage-ambiguous stem cell leukemias.292. The gene discussed is BCL11B; the disease is acute myeloid leukemia.