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t(12;21)(p13;q22)

Identity

 
  t(12;21)(p13;q22) R- bandind and FISH - Courtesy Hossein Mossafa.

Clinics and Pathology

Disease B cell ALL
Phenotype / cell stem origin L1 and L2, CD10+
Epidemiology 15 to 35% of paediatric B-lineage ALL: so far the most frequent translocation in this group; rare or absent in adults and in infants; age: children; no case >20 yrs so far; male and female equally represented
Clinics standard ALL
Prognosis CR in all cases; prognosis seems good

Cytogenetics

Cytogenetics Morphological t(12;21) often remained undetected
Cytogenetics Molecular easily detected by chromosomes 12 and 21 painting or specific probes
Additional anomalies frequent del(12)(p12) on the other chromosome; in rare cases duplication of der(21)t(12;21); looks like a +21
Variants t(6;12;21), t(3;12;21)

Genes involved and Proteins

Gene Name ETV6
Location 12p12
Protein contains a HLH domain and a ETS-DNA binding domain; ETS-related transcription factor
Gene Name AML1
Location 21q22
Dna / Rna transcription is from telomere to centromere
Protein contains a Runt domain and, in the C-term, a transactivation domain; forms heterodimers; widely expressed; nuclear localisation; transcription factor (activator) for various hematopoietic-specific genes

Result of the chromosomal anomaly

Hybrid gene
 
  ETV6 (TEL) and RUNX1 (AML1) breakpoints in the t(12;21) / 5' ETV6 - 3' RUNX1 fusion gene - Courtesy Hossein Mossafa.
Description TEL-AML1 chimaeric gene; 5' centromere to 3' telomere orientation
Transcript the fusion transcript on chromosome 21 TEL -AML1 is the crucial one; the AML1-TEL transcript is absent in some cases; the other TEL allele is often deleted.
Detection RT-PCR of the fusion transcript
  
Fusion Protein
Description Helix loop helix of TEL fused to the nearly entire AML1 protein, comprising the Runt domain and the transactivation domain
  

External links

Other databaset(12;21)(p13;q22) Mitelman database (CGAP - NCBI)

Other genes implicated (Data extracted from papers in the Atlas)

Genes RUNX1 ETV6 MIR100

Bibliography

High frequency of t(12;21) in childhood B-lineage acute lymphoblastic leukemia.
Romana SP, Poirel H, Leconiat M, Flexor MA, Mauchauffˆ© M, Jonveaux P, Macintyre EA, Berger R, Bernard OA
Blood. 1995 ; 86 (11) : 4263-4269.
PMID 7492786
 
The 12;21 translocation involving TEL and deletion of the other TEL allele: two frequently associated alterations found in childhood acute lymphoblastic leukemia.
Raynaud S, Cave H, Baens M, Bastard C, Cacheux V, Grosgeorge J, Guidal-Giroux C, Guo C, Vilmer E, Marynen P, Grandchamp B
Blood. 1996 ; 87 (7) : 2891-2899.
PMID 8639909
 
Fusion of PDGF receptor beta to a novel ets-like gene, tel, in chronic myelomonocytic leukemia with t(5;12) chromosomal translocation.
Golub TR, Barker GF, Lovett M, Gilliland DG
Cell. 1994 ; 77 (2) : 307-316.
PMID 8168137
 
REVIEW articlesautomatic search in PubMed
Last year articlesautomatic search in PubMed

Contributor(s)

Written08-1997Jean-Loup Huret and Alain Bernheim
Laboratoire de Cytogénétique, UMR 1599 CNRS, Institut Gustave Roussy, 94805 Villejuif, France

Citation

This paper should be referenced as such :
Huret JL and Bernheim A . t(12;21)(p13;q22). Atlas Genet Cytogenet Oncol Haematol. August 1997 .
URL : http://AtlasGeneticsOncology.org/Anomalies/t1221.html

The various updated versions of this paper are referenced and archived by INIST as such :
http://documents.irevues.inist.fr/bitstream/handle/2042/32031/08-1997-t1221.pdf   [ Bibliographic record ]

© Atlas of Genetics and Cytogenetics in Oncology and Haematology
indexed on : Thu Apr 17 12:09:24 CEST 2014


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