A new recurrent and specific cryptic translocation, t(5;14)(q35;q32), is associated with expression of the Hox11L2 gene in T acute lymphoblastic leukemia

FISH identified a cryptic t(5;14)(q35;q32) in T acute lymphoblastic leukemi a (ALL), whereas it was not observed in B ALL samples. This translocation i s present in five out of 23 (22%) children and adolescents with T ALL teste d. RanBP17, a gene coding for a member of the importin beta protein family, and Hox11Like2, an orphan homeobox gene were mapped close to the chromosom e 5 breakpoints and CTIP2, which is highly expressed during normal T cell d ifferentiation, was localized in the vicinity of the chromosome 14 breakpoi nts. The Hox11L2 gene was found to be transcriptionally activated as a resu lt of the translocation, probably under the influence of CTIP2 transcriptio nal regulation elements. These data establish the t(5;14)(q35;q32) as a maj or abnormality, and Hox11 family member activation as an important pathway in T ALL leukemogenesis.