t(5;14)(q35;q32) BCL11B/TLX3

2002-06-01   Roland Berger 

1.Inserm U 434 and SD 401 No. 434 CNRS, Institut de Génétique Moléculaire, 27, rue Juliette Dodu, 75010 Paris, France
2.Genetics, Dept Medical Information, University of Poitiers, CHU Poitiers Hospital, F-86021 Poitiers, France

Clinics and Pathology

Disease

T cell acute lymphoblastic leukemia (ALL)

Phenotype stem cell origin

cortical T cell leukemia (CD1a+,CD10+)

Epidemiology

frequent in T-cell ALL in children (in about 20% of childhood T-cell ALLs); less frequent in adult T-ALL. Not seen in B-cell ALL

Cytology

FAB nomenclature: L1 or L2 ALL

Prognosis

present data suggest that t(5;14)(q35;q32) is associated with poor outcome, but confirmatory data is necessary prior to conclude

Cytogenetics

Cytogenetics morphological

Cryptic translocation (banded karyotype). Often apparently normal karyotype with banding techniques.

Cytogenetics molecular

t(5;14)(q35;q32) can be detected with FISH techniques. Several probes may be used: chromosome painting, combination of painting probes and YAC, multicolor-FISH with adequate probes. The localization of the chromosomal breakpoint with BACs/PACs will be performed in a second step.

Additional anomalies

variable

Genes Involved and Proteins

Note
The consequence of the translocation is the ectopic expression of the HOX11L2, gene normally located to 5q35, and normally not expressed in ALL without 5q rearrangement. The "deregulation" of HOX11L2 expression is thought to result from abnormal control of the gene by CTPI2, located to 14q32, as a consequence of the chromosomal rearrangement. The chromosome 5 breakpoint is usually located within the locus of another gene, RanBP17, often disrupted by the chromosomal rearrangement. The breakpoint on chromosome 5 is consequently distant from the gene abnormally expressed (HOX11L2).
Gene name
TLX3 (T-cell leukemia, homeobox protein 3)
Location
5q35.1
Protein description
homeobox domain; belongs to HOX 11 family

Result of the Chromosomal Anomaly

Description

no fusion protein, but abnormal expression of HOX11L2

Oncogenesis

HOX11L2 is transcriptionally activated, due to control by CITP2 regulatory sequences.

Bibliography

Pubmed IDLast YearTitleAuthors
121305132002HOX11L2 expression defines a clinical subtype of pediatric T-ALL associated with poor prognosis.Ballerini P et al
115872052001A new recurrent and specific cryptic translocation, t(5;14)(q35;q32), is associated with expression of the Hox11L2 gene in T acute lymphoblastic leukemia.Bernard OA et al
120868902002Gene expression signatures define novel oncogenic pathways in T cell acute lymphoblastic leukemia.Ferrando AA et al
118402572002Translocation t(5;14)(q35;q32) in three cases of childhood T cell acute lymphoblastic leukemia: a new recurring and cryptic abnormality.Hélias C et al

Summary

Fusion gene

BCL11B/TLX3 BCL11B (14q32.2) TLX3 (5q35.1) M t(5;14)(q35;q32)
Atlas Image
t(5;14)(q35;q32) FISH - Courtesy Melanie Zenger and Claudia Haferlach.

Citation

Roland Berger

t(5;14)(q35;q32) BCL11B/TLX3

Atlas Genet Cytogenet Oncol Haematol. 2002-06-01

Online version: http://atlasgeneticsoncology.org/haematological/1227/t(5;14)(q35;q32)

Historical Card

2002-02-01 t(5;14)(q35;q32) BCL11B/TLX3 by  Jean-Loup Huret 

Genetics, Dept Medical Information, University of Poitiers, CHU Poitiers Hospital, F-86021 Poitiers, France