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Incidence of TCR and TCL1 Gene Translocations and Isochromosome 7q in Peripheral T-Cell Lymphomas Using Fluorescence In Situ Hybridization

Andrew L. Feldman MD, Mark Law, Karen L. Grogg MD, Erik C. Thorland PhD, Stephanie Fink, Paul J. Kurtin MD, William R. Macon MD, Ellen D. Remstein MD, Ahmet Dogan MD, PhD
DOI: http://dx.doi.org/10.1309/PNXUKA1CFJMVGCN1 178-185 First published online: 1 August 2008


Translocations involving the T-cell receptor (TCR) and TCL1 genes occur in T-cell precursor lymphoblastic leukemia/lymphoma and prolymphocytic leukemia; isochromosome 7q has been associated with hepatosplenic T-cell lymphoma. However, the incidence of these abnormalities in peripheral T-cell lymphomas (PTCLs) as a whole has not been well defined.

We studied genetic abnormalities in 124 PTCLs seen at the Mayo Clinic, Rochester, MN, between 1987 and 2007. Tissue microarrays were screened using 2-color break-apart fluorescence in situ hybridization probes flanking the TCRα (TCRA, 14q11), TCRβ (TCRB, 7q35), and TCRγ (TCRG, 7p15) genes and the TCL1 gene (14q32). Isochromosome 7q was analyzed by using a 2-color probe to 7p and 7q32.1.

Translocations involved TCRA in 3 (2.9%) of 102 cases and TCRB in 1 (1%) of 88. Isochromosome 7q was detected in 2 cases of extranodal NK/T-cell lymphoma, nasal type, and 2 cases of anaplastic lymphoma kinase–negative anaplastic large cell lymphoma. One of the latter cases also had a translocation of TCRA, and further studies confirmed a novel t(5;14) translocation.

Key Words:
  • Peripheral T-cell lymphoma
  • Extranodal NK/T-cell lymphoma
  • Cytogenetics
  • Fluorescence in situ hybridization
  • T-cell receptor
  • TCL1
  • Isochromosome 7q