Atlas of Genetics and Cytogenetics in Oncology and Haematology
t(7;12)(q34;p13)
t(12;14)(p13;q11)
| Identity |
| 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 | TCRA |
| Location | 14q11 |
| Protein | T-cell receptor alpha |
| Gene Name | TCRD (TRD@) |
| Location | 14q11 |
| Protein | T-cell receptor delta |
| Gene Name | TCRB |
| Location | 7q34 |
| Protein | T-cell receptor beta |
| Result of the chromosomal anomaly |
| 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. |
| 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. |
| External links |
| Other database | t(7;12)(q34;p13) | Mitelman database (CGAP - NCBI) | |
| Other database | t(12;14)(p13;q11) | Mitelman database (CGAP - NCBI) |
| 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 |
| 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 |
| 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, Bjrgvinsdttir H, Strmbeck 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 |
| Contributor(s) |
| Written | 06-2006 | Emmanuelle 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 |
| 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. June 2006 . URL : http://AtlasGeneticsOncology.org/Anomalies/t0712q34p13ID1434.html |
This paper is referenced by INIST as such : |
| http://documents.irevues.inist.fr/bitstream/2042/38362/1/06-2006-t0712q34p13ID1434.pdf [ Bibliographic record ] |
| © Atlas of Genetics and Cytogenetics in Oncology and Haematology | indexed on : Sat Mar 9 12:37:25 CET 2013 |
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