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TCRB (TRB) Breakapart

Applications
haematology
Catalogue Numbers
LPH 048 (10 tests)
LPH 048-S (5 tests)

Dysregulation of normal transcription is a feature of all types of acute leukaemia. In T-ALL, this is brought about by altered expression of normal transcription factor proteins, which is in contrast with AML and B-ALL, where chimaeric proteins are expressed and provide the drivers for the malignancy.

T-ALL composes around 12-15% of childhood ALL1. In about 30% of these cases, chromosomal rearrangements involving the T-cell receptor genes TRA@ (TCRA), TRB@ (TCRB), TRG@ (TCRG) and TRD@ (TCRD) have been described2. It has been suggested that a number of developmentally important transcription factor genes are dysregulated as a result of being brought into close proximity with the promoter and enhancer elements of one of these T-cell receptor genes3. These can be more clearly demonstrated by FISH than by using conventional cytogenetics4.

The TCRB T-cell Receptor gene on chromosome 7q34 is rearranged with the genes TLX1, HOX@, LYL1, TAL2, LCK and NOTCH1 following the t(7;10)(q34;q24); t(7;7)(p15;q34); t(7;19)(q34;p13); t(7;9)(q34;q32); t(1;7)(p34;q34) and t(7;9)(q34;q34) translocations respectively. The frequency of rearrangements varies between 7% (for the TLX1 rearrangement) to less than 1% (for TAL2, LYL1, LCK and NOTCH1)5.

References

1. Schneider NR et al., Blood 2000;96:2543-9

2. Secker-Walker LM, Chromosomes and Genes in Acute Lymphoblastic Leukaemia. New York: Chapman and Hall 1997

3. Raimondi SC. T-lineage acute lymphoblastic leukemia (T-ALL) Atlas Genet Cytogenet Oncol Haematol. May 2007

4. Gesk S et al., Leukemia 2003;17:738-45

5. Graux C et al., Leukemia 2006;20:1496-510

Microscope Images

TCRB (TRB) Breakapart magnified
Area of Interest*
ALL

Disclaimer

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.