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t(7;12)(q34;p13) TRB/CCND2

t(12;14)(p13;q11) TRA or TRD/CCND2

Written2006-06Emmanuelle Clappier, Jean Soulier
Laboratoire central d'Hématologie et U728 INSERM Institut Universitaire d'Hématologie Hopital Saint-Louis et Université Paris 7 1, AV Claude Vellefaux 75010 Paris, France

(Note : for Links provided by Atlas : click)

Identity

ICD-Topo C420,C421,C424 BLOOD, BONE MARROW, & HEMATOPOIETIC SYS
ICD-Morpho 9837/3 T lymphoblastic leukaemia/lymphoma
Atlas_Id 1434
Note The 2 translocations are variants of each other, and probably share the same biological significance
 
  R-band analysis. Partial karyotypes showing t(7;12)(q34;p13) (left panel), and t(12;14)(p13;q11) (right panel)

Clinics and Pathology

Disease T cell acute lymphoblastic leukemia (T-ALL)
Phenotype / cell stem origin T cell precursor. These translocations are not restricted to a single maturation stage.
Epidemiology less than 5% among T-ALL.
Cytology Lymphoblasts

Cytogenetics

Cytogenetics Morphological t(7;12)(q34;p13) may be barely detectable by chromosome banding techniques alone.
 
  Example of FISH performed on bone marrow metaphase from a patient with t(7;12)(q34;p13). Dual color FISH using whole chromosome paint for chromosome 7 (green) and chromosome 12 (red) showed the reciprocal translocation.
Cytogenetics Molecular Rearrangement of the CCND2 locus at 12p13.3 may be detected by dual color FISH using CCND2 flanking probes.
 
  Example of double colour FISH performed on bone marrow interphasic nuclei from a patient with t(7;12)(q34;p13) using CCND2 flanking probes at 12p13. The centromeric BAC clone RP11-388F6 (red) and the telomeric BAC clone RP11-320N7 (green) show one fusion signal at the normal chromosome 12, and dissociated signals at der(12) (red signal) and der(7) (green signal).

Genes involved and Proteins

Note The t(7;12)(q34;p13) translocation has not to be confused with the t(7;12)(q36;p13) involving ETV6 at 12p13.1 and HLXB9 at 7q36, which is found in infant myeloid leukemias.
Gene Name CCND2
Location 12p13.3
Dna / Rna 5 exons, 2.1 kb mRNA, 5'-3' telomere to centromere orientation.
Protein Cyclin D2; 289 amino acids; 33 kDa. Cyclin D2 is a regulator of the progression through G1-phase and G1 to S-phase transition of the cell cycle.
Gene Name TRA
Location 14q11
Protein T-cell receptor alpha
Gene Name TRD
Location 14q11
Protein T-cell receptor delta
Gene Name TRB
Location 7q34
Protein T-cell receptor beta

Result of the chromosomal anomaly

Hybrid gene
Note No fusion protein
Description t(7;12)(q34;p13) and t(12;14)(p13;q11) translocations result in juxtaposition of TRA/D or TRB regulatory sequences to the CCND2 gene, leading to deregulated expression of the CCND2 gene.
  
Fusion Protein
Note T-ALL cases with t(7;12)(q34;p13) or t(12;14)(p13;q11) can be associated to other oncogenic abnormalities, such as overexpression of the oncogenes TAL1, TLX3/HOX11L2, or HOXA genes, activating NOTCH1 mutations, and/or CDKN2A/p16/ARF locus deletion.
Oncogenesis CCND2 gene expression is tightly regulated throughout thymocyte differenciation. Its deregulated expression in T-ALL cases with t(7;12)(q34;p13) or t(12;14)(p13;q34) is likely to play a role in T-cell oncogenesis.
  

To be noted

Additional cases are needed to delineate the epidemiology of this rare entity:
you are welcome to submit a paper to our new Case Report section.

Bibliography

Cyclin D2 dysregulation by chromosomal translocations to TCR loci in T-cell acute lymphoblastic leukemias.
Clappier E, Cuccuini W, Cayuela JM, Vecchione D, Baruchel A, Dombret H, Sigaux F, Soulier J
Leukemia : official journal of the Leukemia Society of America, Leukemia Research Fund, U.K. 2006 ; 20 (1) : 82-86.
PMID 16270038
 
Deregulation of cyclin D2 by juxtaposition with T-cell receptor alpha/delta locus in t(12;14)(p13;q11)-positive childhood T-cell acute lymphoblastic leukemia.
Karrman K, Andersson A, Björgvinsdóttir H, Strömbeck B, Lassen C, Olofsson T, Nguyen-Khac F, Berger R, Bernard O, Fioretos T, Johansson B
European journal of haematology. 2006 ; 77 (1) : 27-34.
PMID 16548914
 
A new breakpoint, telomeric to TEL/ETV6, on the short arm of chromosome 12 in T cell acute lymphoblastic leukemia.
Le Coniat M, Della Valle V, Marynen P, Berger R
Leukemia : official journal of the Leukemia Society of America, Leukemia Research Fund, U.K. 1997 ; 11 (8) : 1360-1363.
PMID 9264392
 

Citation

This paper should be referenced as such :
Clappier, E ; Soulier, J
t(7;12)(q34;p13) - t(12;14)(p13;q11)
Atlas Genet Cytogenet Oncol Haematol. 2006;10(4):276-278.
Free journal version : [ pdf ]   [ DOI ]
On line version : http://AtlasGeneticsOncology.org/Anomalies/t0712q34p13ID1434.html


Translocations implicated (Data extracted from papers in the Atlas)

 t(12;14)(p13;q11)
 t(7;12)(q34;p13) TRB/CCND2

External links

TRB (-) CCND2 (12p13.32)

Mitelman databaset(12;14)(p13;q11) [Case List]    t(12;14)(p13;q11) [Association List] Mitelman database (CGAP - NCBI)
Mitelman databaset(7;12)(q34;p13) [Case List]    t(7;12)(q34;p13) [Association List] Mitelman database (CGAP - NCBI)
arrayMapTopo ( C42) Morph ( 9837/3) - arrayMap (UZH-SIB Zurich)  [auto + random 100 samples .. if exist ]   [tabulated segments]
 
Mitelman databaseTRB/CCND2 [MCList]  TRB (-) CCND2 (12p13.32)
 
Disease databaset(7;12)(q34;p13) TRB/CCND2
REVIEW articlesautomatic search in PubMed
Last year articlesautomatic search in PubMed
All articlesautomatic search in PubMed


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