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TCRAD Breakapart

Catalogue Numbers
LPH 047-S (5 tests)
LPH 047 (10 tests)

Probe Specification

  • TCRAD, 14q11.2, Red
  • TCRAD, 14q11.2, Green

The TCRAD product consists of a 225kb probe, labelled in red, located at the centromeric end of the Variable Region of the immunoglobulin gene cluster, including the G36107 marker and a green probe covering a 143kb region located telomeric to the TRAC gene, including the entire OXA1L gene and the G35927 marker.

Probe Information

Chromosomal translocations with breakpoints in alpha and delta T-cell receptor (TCR) gene loci at 14q11.2 are recurrent in several T-cell malignancies including T-cell acute lymphoblastic leukaemia (T-ALL)1.

T-cell acute lymphoblastic leukaemia (T-ALL) is an aggressive malignancy of the lymphoblasts committed to the T-cell lineage and represents 15% of childhood and 25% of adult ALL2,3. Karyotyping reveals recurrent translocations that activate a small number of oncogenes in 25-50% of T-ALLs but, with FISH, further cryptic abnormalities can be revealed2.

The most common chromosomal rearrangements, found in about 35%2 of T-ALLs, involve the alpha and delta T-cell receptor loci (TRA and TRD) at 14q11.2, the beta TCR locus (TRB) at 7q34 and the gamma TCR (TRG) at 7p14. In most cases the juxtaposition of oncogenes next to the TCR regulatory sequences leads to the deregulated expression of these genes2,4,5.

The TRA/D complex at 14q11.2 has been shown to be involved in a number of different translocations in T-ALL. These include the t(10;14)(q24;q11) involving TLX1; the t(1;14)(p32;q11) involving TAL1; the t(14;21)(q11;q22) involving the OLIG2; the t(11;14)(p15;q11) involving LMO1 and the t(11;14)(p13;q11) involving LMO22.

In addition to T-ALL, TRA/D translocations are recurrent in T-non- Hodgkin’s lymphoma and T-prolymphocytic leukaemia. They have also been reported in cases of ataxia telangiectasia (AT)1.

The quality of the products we have received from Cytocell have been excellent. The FISH probes they provide to us give intense, strong signals and are a pleasure to count. What has really stood out however has been the level of support and assistance provided by Cytocell’s application specialists. The team worked very closely alongside our own during the adoption of this product and spent many hours with us perfecting the technique, going above and beyond what I would expect during the transition period. Source BioScience absolutely demand high quality products and service to be able to deliver our results with confidence, and that is what we have received from Cytocell. Neil Ryan, Laboratory Operations Manager at Source BioScience


  1. Rack et al., Blood 1997;90(3):1233-1240
  2. Graux et al., Leukemia 2006;20:1496-1510
  3. Cauwelier et al., Leukemia 2007;21:121-128
  4. Swerdlow et al.,editors, WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues, Lyon, France, IARC:2008
  5. Gesk et al., Leukemia 2003;17:738-745
  6. Arsham, MS., Barch, MJ. and Lawce HJ. (eds.) (2017) The AGT Cytogenetics Laboratory Manual. New Jersey: John Wiley & Sons Inc.
  7. Mascarello JT, Hirsch B, Kearney HM, et al. Section E9 of the American College of Medical Genetics technical standards and guidelines: fluorescence in situ hybridization. Genet Med. 2011;13(7):667-675.
  8. Wiktor AE, Dyke DLV, Stupca PJ, Ketterling RP, Thorland EC, Shearer BM, Fink SR, Stockero KJ, Majorowicz JR, Dewald GW. Preclinical validation of fluorescence in situ hybridization assays for clinical practice. Genetics in Medicine. 2006;8(1):16–23.

Microscope Images

TCRAD Breakapart magnified
Area of Interest*


This product is intended to be used on Carnoy’s solution (3:1 methanol/acetic acid) fixed haematological samples.

*Disease information supported by the literature and is not a reflection of the intended purpose of this product.