Short communication A novel t(6;14)(q25~q27;q32) in acute myelocytic leukemia involves the BCL11B gene

Abstract Cytogenetic studies in a patient with acute myelocytic leukemia (AML) revealed as the sole karyo-typic alteration a half-cryptic rearrangement, identified with 48-color combined binary ratio-labeledfluorescence in situ hybridization (pq-COBRA-FISH) as a reciprocal t(6;14)(q?;q?). The breakpointswere later assigned on the basis of G-banding to t(6;14)(q25~q26;q32). FISH experiments usinggenomic probes showed that the breakpoint on 14q32.2 was within bacterial artificial chromosomeRP11-782I5 and revealed BCL11B as the only candidate gene in the region. BCL11B is a homologto BCL11A (2p13), a highly conserved gene implicated in mouse and human leukemias. To ourknowledge,this isthefirstreportimplicating BCL11B inhematologicalmalignancies.Because oflackof material, the translocation partner remains unknown. 2004 Elsevier Inc. All rights reserved. 1. Introduction Cytogenetic analysis is a valuable determinant in thediagnosis of patients with acute myelocytic leukemia(AML). It not only provides an important basis for clinicalmanagement, but can also lead to recognition of leukemo-genic pathways, potentially increasing the prospects oftarget-specific therapy [1–3]. Up to 40%–50% of adult AMLpatients, however, present normal karyotypes [1,2]. It haslong been postulated that these apparently normal karyo-types in AML may harbor unidentified rearrangements [4].In a percentage of these cases, rearrangements are missedbecause of poor chromosome morphology or complexity ofkaryotypes, in which different multicolor FISH approaches[5–7]haveprovenusefulinelucidatinghematologicalkaryo-types [8,9]. Alternatively, some rearrangements might bebelow the resolution level of conventional cytogenetics butcouldpossiblyberevealedwithmolecular[10,11]ormolecu-lar cytogenetic [12] methods. We describe the use of molec-ular karyotyping to elucidate a half-cryptic rearrangement,leading to the identification of