t(14;21)(q11;q22) TRA/OLIG2

2004-11-01   Jacques Boyer 

1.Laboratoire d hématologie, CH du MANS, France

Clinics and Pathology

Disease

T-cell Acute lymphoblastic leukemia (T-ALL)

Epidemiology

Rare.

Clinics

One case reported: The patient was a 7-years-old female with high white blood count with lymphoblasts positive for T-cell antigens; cerebrospinal fluid négative for malignant cells; superior mediastinal mass.

Prognosis

The patient attained a complete remission with standard chemotherapy but relapsed and died after 4 months of therapy.

Genes Involved and Proteins

Gene name
TRA (T cell Receptor Alpha)
Location
14q11.2
Protein description
T cell receptor
Gene name
OLIG2 (oligodendrocyte lineage transcription factor)
Location
21q22.11
Note
alias OLIG2
Dna rna description
This gene maps within a 9 to 12 Mb region of chromosome 21q22.
Protein description
This gene was shown to possess a helix-loop-helix (bHLH) motif witch inhibits the E2A function in transfection assays. E2A is required for normal T-cell differentiation.

Result of the Chromosomal Anomaly

Note

Translocation of the BHLHB1 gene 130kb upstream of the TCRA enhancer. This translocation activates the BHLHB1 gene and produces high levels of BHLHB1 mRNA. Expression of HLHB1 inhibits E2A-mediated transcription activation in vitro.No fusion protein.

Oncogenesis

Several helix-loop-helix (HLH) proteins are proposed to function as transcriptionnal regulatory factors based on their ability to bind in vitro the E-box motif of transcriptional enhancers. The observation that ectopic BHLHB1 expression can onhibit E2A activity suggests that BHLHB1 exerts its leukemogenic effects through a functional inhibition of E2A.

Bibliography

Pubmed IDLast YearTitleAuthors
86053271996Cytogenetic abnormalities in adult acute lymphoblastic leukemia: correlations with hematologic findings outcome. A Collaborative Study of the Group Français de Cytogénétique Hématologique.
92347341997E2A deficiency leads to abnormalities in alphabeta T-cell development and to rapid development of T-cell lymphomas.Bain G et al
107378012000The t(14;21)(q11.2;q22) chromosomal translocation associated with T-cell acute lymphoblastic leukemia activates the BHLHB1 gene.Wang J et al
80900321994t(5;14)(q33-34;q11), a new recurring cytogenetic abnormality in childhood acute leukemia.Whitlock JA et al

Summary

Fusion gene

TRA/OLIG2 TRA (-) OLIG2 (21q22.11) M t(14;21)(q11;q22)

Citation

Jacques Boyer

t(14;21)(q11;q22) TRA/OLIG2

Atlas Genet Cytogenet Oncol Haematol. 2004-11-01

Online version: http://atlasgeneticsoncology.org/haematological/1180/t(14;21)(q11;q22)-tra-olig2

External Links