t(3;7)(q27;q32) FRA7H/BCL6

2012-12-01   Jean-Loup Huret 

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

Clinics and Pathology

Disease

Non Hodgkin lymphoma

Clinics

Only 3 cases to date of t(3;7)(q27;q32): a B-cell lymphoma cell line established from a 55-year-old male patient with terminal diffuse large B-cell lymphoma (DLBCL), a t(11;14)(q23;q32) and a complex karyotype (Schneider et al., 2008); a 54-year-old male patient with stade IV splenic marginal zone B-cell lymphoma (SMZL) and a complex karyotype with +3 whos survival was 9 years+ (Boonstra et al., 2003); and a female patient with stade IV SMZL and a complex karyotype (Ott et al., 2000).

Note

The molecular event involving FRA7H and BCL6 has been uncovered only in the most recent report (Schneider et al., 2008).

Genes Involved and Proteins

Gene name
BCL6 (B-Cell Lymphoma 6)
Location
3q27.3
Protein description
706 amino acids; composed of a NH2-term BTB/POZ domain (amino acids 1-130 (32-99 according to Swiss-Prot) which mediates homodimerization and protein-protein interactions with other corepressors (including HDAC1 and NCOR2/SMRT to constitute a large repressing complex, another transcription repression domain (191-386), PEST sequences (300-417) with a KKYK motif (375-379), and six zinc finger at the C-term (518-541, 546-568, 574-596, 602-624, 630-652, 658-681), responsible for sequence specific DNA binding. Transcription repressor; recognizes the consensus sequence: TTCCT(A/C)GAA (Albagli-Curiel, 2003). Role in germinal centers of lymphoid follicles. BCL6 prevents ATM and TP53 to induce apoptosis in response to DNA rearrangements such as somatic hypermutation and class switch recombination. Therefore essential for normal B cell development.
Gene name
FRA7H (fragile site, aphidicolin type, common, fra(7)(q32.3))
Location
7q32.3
Note
Fragile site, aphidicolin type, common.

Result of the Chromosomal Anomaly

Description

The breakpoint at 7q32 maps within FRA7H; the breakpoint on chromosome 3 lies upstream of exon 1, out of both the major breakpoint region (MBR) and the alternative breakpoint regions (ABR). Hence, BCL6 is constitutively, albeit moderately, expressed (Schneider et al., 2008).

Bibliography

Pubmed IDLast YearTitleAuthors
125550642003Ambivalent role of BCL6 in cell survival and transformation.Albagli-Curiel O et al
146813212003Splenic marginal zone lymphomas presenting with splenomegaly and typical immunophenotype are characterized by allelic loss in 7q31-32.Boonstra R et al
108620462000Marginal zone B-cell lymphomas (MZBL) arising at different sites represent different biological entities.Ott MM et al
179897152008T(3;7)(q27;q32) fuses BCL6 to a non-coding region at FRA7H near miR-29.Schneider B et al

Citation

Jean-Loup Huret

t(3;7)(q27;q32) FRA7H/BCL6

Atlas Genet Cytogenet Oncol Haematol. 2012-12-01

Online version: http://atlasgeneticsoncology.org/haematological/1630/t(3;7)(q27;q32)

External Links