Download Leukaemia Section t(12;21)(p12;q22) Atlas of Genetics and Cytogenetics

Atlas of Genetics and Cytogenetics
in Oncology and Haematology
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Leukaemia Section
Short Communication
t(12;21)(p12;q22)
Jean-Loup Huret, Alain Bernheim
Genetics, Dept Medical Information, University of Poitiers, CHU Poitiers Hospital, F-86021 Poitiers, France
(JLH);
Laboratoire de Cytogénétique, UMR 1599 CNRS, Institut Gustave Roussy, 94805 Villejuif, France (AB)
Published in Atlas Database: August 1997
Online version is available at: http://AtlasGeneticsOncology.org/Anomalies/t1221.html
DOI: 10.4267/2042/32031
This work is licensed under a Creative Commons Attribution-Non-commercial-No Derivative Works 2.0 France Licence.
© 1997 Atlas of Genetics and Cytogenetics in Oncology and Haematology
Clinics and pathology
Genes involved and Proteins
Disease
ETV6
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.
Location: 12p13
DNA / RNA
9 exons; alternate splicing.
Protein
Contains a HLH domain and a ETS-DNA binding
domain; wide expression; nuclear localisation; ETSrelated transcription factor.
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.
Cytogenetics
Cytogenetics, morphological
t(12;21) often remained undetected.
Easily detected by chromosomes 12 and 21 painting or
specific probes.
Results of the chromosomal
anomaly
Additional anomalies
Hybrid gene
Frequent del(12)(p12) on the other chromosome; in
rare cases duplication of der(21)t(12;21); looks like a
+21.
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.
Cytogenetics, molecular
Variants
t(6;12;21), t(3;12;21)
Atlas Genet Cytogenet Oncol Haematol. 1997; 1(1)
19
t(12;21)(p12;q22)
Huret JL, Bernheim A
Romana SP, Poirel H, Leconiat M, Flexor MA, Mauchauffé M,
Jonveaux P, Macintyre EA, Berger R, Bernard OA. High
frequency of t(12;21) in childhood B-lineage acute
lymphoblastic leukemia. Blood 1995 Dec 1; 86(11):4263-9.
Raynaud S, Cave H, Baens M, Bastard C, Cacheux V,
Grosgeorge J, Guidal-Giroux C, Guo C, Vilmer E, Marynen P,
Grandchamp B. The 12; 21 translocation involving TEL and
deletion of the other TEL allele: two frequently associated
alterations found in childhood acute lymphoblastic leukemia.
Blood 1996 Apr 1; 87(7):2891-9.
Detection protocol
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.
References
This article should be referenced as such:
Huret JL, Bernheim A. t(12;21)(p12;q22).
Cytogenet Oncol Haematol.1997;1(1):19-20.
Golub TR, Barker GF, Lovett M, Gilliland DG. Fusion of PDGF
receptor beta to a novel ets-like gene, tel, in chronic
myelomonocytic
leukemia
with
t(5;12)
chromosomal
translocation. Cell 1994 Apr 22; 77(2):307-16.
Atlas Genet Cytogenet Oncol Haematol. 1997; 1(1)
20
Atlas
Genet