t(14;15)(q32;q11) IGH/NBEAP1

2008-07-01   Gianluca Gaidano , Silvia Rasi 

1.Division of Hematology, Department of Clinical, Experimental Medicine Center of Biotechnologies for Applied Medical Research, Amedeo Avogadro University of Eastern Piedmont, Via Solaroli 17, 28100 Novara, Italy
2.Division of Hematology, Department of Clinical, Experimental Medicine & Center of Biotechnologies for Applied Medical Research, Amedeo Avogadro University of Eastern Piedmont, Via Solaroli 17, 28100 Novara, Italy

Clinics and Pathology

Disease

Diffuse large B-cell lymphoma (DLBCL). DLBCL is a molecularly heterogeneous type of aggressive lymphoma, accounting for approximately 40% of all B-cell non-Hodgkin lymphomas (NHL) of the Western world. Translocations involving the chromosomal region 15q11-13 also have been identified in nonlymphoid tumors.

Phenotype stem cell origin

B-cell. The chromosomal translocation t(14;15)(q32;q11-13) can activate BCL8 gene expression in lymphoid tissues, whereas BCL8 expression is not normally found in hematopoietic tissues.

Epidemiology

Translocations affecting 15q11-q13 and various chromosomal partners occur in about 3-4% of DLBCL.

Clinics

At present, it is not not yet clear whether chromosomal translocation (t14;15) identifies a homogeneous.

Pathology

Clinico-pathologic subtype of DLBCL.

Prognosis

The effect of BCL8 expression on the prognosis of patients has yet to be investigated.

Cytogenetics

Additional anomalies

DLBCL is a heterogeneous disease with respect to karyotypic abnormalities. t(14;15)(q32;q11-13)is a rare chromosomal translocation restricted to 4-5% DLBCL. The most frequent cytogenetic abnormalities detected in DLBCL involve BCL6 t(3;V)(q27;V), BCL2 t(14;18)(q32;q21), and myc t(8;14)(q24;q32), and occur in 25%, 20% and 10% of DLBCL, respectively.

Variants

In addition to IGHV gene translocation, other translocations of the chromosomal region 15q11-13 involve additional chromosomal sites, including 22q11 (IGLV), 9p13, 1p32,7p13, 12q24, and 15q22.

Genes Involved and Proteins

Gene name
IGH (Immunoglobulin Heavy)
Location
14q32.33
Dna rna description
IgH gene is composed of V (variable), D (diversity), J (joining), and C (constant) segments. During B cell development, a recombination event at the DNA level creates a rearranged IGHV-D-J gene.
Protein description
Proteins encoded by the IgH gene are the immunoglobulin heavy chains.
Gene name
NBEAP1 (B-cell CLL/lymphoma 8)
Location
15q11.2
Dna rna description
3 exons. The 5part of exon 1 and the 3part of exon 3 are non coding. Two alternative transcripts: a major transcript of 2.6Kb, and a less expressed transcript of 4.5Kb, due to differential polyadenylation.
Protein description
100 amino acids, predicted molecular weight of 19 kDa; predicted: similar to protein neurobeachin (Lysosomal trafficking regulator 2). Truncated polypeptides with uncertain function are also produced.

Result of the Chromosomal Anomaly

Description

The translocation t(14;15)(q32;q11-13) leaves the coding region of BCL8 gene intact, and does not lead to the formation of a hybrid gene. BCL8 is adjacent to the chromosomal breakpoint, that is located upstream of a rearranged VH segment. BCL8 is a part of a large duplicated region within 15q11 containing several pseudogenes, including orphan IGH copies of V and D segments and its possible that this V/D segments can rearrange with D/J segments on chromosome 14.the chromosomal translocation does not lead to the formation of a fusion protein.

Oncogenesis

t(14;15)(q32;q11-13) causes activation of the BCL8 proto-oncogene by deregulated expression of BCL8. This chromosomal translocation may contribuite to lymphomagenesis by alterated expression level of BCL8.

Bibliography

Pubmed IDLast YearTitleAuthors
121607292002BCL8 is a novel, evolutionarily conserved human gene family encoding proteins with presumptive protein kinase A anchoring function.Dyomin VG et al
91591411997BCL8, a novel gene involved in translocations affecting band 15q11-13 in diffuse large-cell lymphoma.Dyomin VG et al
117015422000Non-Hodgkin's Lymphoma: Molecular Features of B Cell Lymphoma.Macintyre E et al
149727862002Molecular heterogeneity of diffuse large B-cell lymphoma: implications for disease management and prognosis.Rossi D et al

Citation

Gianluca Gaidano ; Silvia Rasi

t(14;15)(q32;q11) IGH/NBEAP1

Atlas Genet Cytogenet Oncol Haematol. 2008-07-01

Online version: http://atlasgeneticsoncology.org/haematological/1349/t(14;15)(q32;q11)