Absence of TCR loci chromosomal translocations in cutaneous T-cell lymphomas.

Chromosomal aberrations involving T-cell receptor (TCR) gene loci have been described in several T-cell malignancies. In primary cutaneous T-cell lymphomas (CTCL), the frequency of these aberrations has not yet been well established. We analyzed TCR gene loci (TCRAD, TCRB, and TCRG) status in CTCLs by fluorescence in situ hybridization (FISH). Twenty-five patients with CTCLs were included in the study: 13 Sézary syndromes (SS), six tumoral stage mycosis fungoides (MFt), and six primary cutaneous anaplastic large cell lymphomas CD30(+) (cALCL-CD30(+)). FISH was performed with three break-apart probes flanking TCRAD (14q11), TCRB (7q34), and TCRG (7p14) loci in each case. TCR gene chromosomal rearrangements were not detected in any of the analyzed cases. Gains of TCRB and TCRG genes were observed in 23% (3 of 13) of SS and 50% (3 of 6) of MFt, reflecting the presence of trisomy and/or tetrasomy of chromosome 7 already detected by conventional cytogenetics and array comparative genetic hybridization techniques. TCR loci rearrangements are not frequent in CTCLs; however, we cannot exclude a pathogenic role in these malignancies.