Atlas of Genetics and Cytogenetics in Oncology and Haematology
t(14;18)(q32;q21) (IgH/BCL2)
t(2;18)(p11;q21)
t(18;22)(q21;q11)
| Identity |
| Note | the 3 translocations are variants of each other, and they share the same clinical significance |
 | |
| Inset top right: t(14;18)(q32;q21) FISH - Courtesy Hossein Mossafa; First row: t(2;18)(p11;q21), G- banding - Courtesy Jean-Luc Lai and Alain Vanderhaegent. Second row: (14;18)(q32;q21), G- banding - Courtesy Jean-Luc Lai and Alain Vanderhaegen (left), and H. Norback, Eric B. Johnson, Sara Morrison-Delap UW Cytogenetic Services (centre); R- banding - Jean Loup Huret (top), and Courtesy Hossein Mossafa (bottom). Third row: t(18;22)(q21;q11), G- banding - Courtesy Jean-Luc Lai and Alain Vanderhaegen (left) ; and, H. Norback, Eric B. Johnson, Sara Morrison-Delap http://www.slh.wisc.edu/cytogenetics (centre). | |
| Clinics and Pathology |
| Disease | B- cell NHL mainly; may (rarely) be found in ALL or in chronic lymphoproliferative diseases |
| Phenotype / cell stem origin | B lymphocyte; the translocation occurs at the pre B cell stage |
| Epidemiology | found in 80 to 90 % of follicular lymphomas, 30% of diffuse large cell lymphomas (sometimes with prior follicular type), rarely in other lymphoproliferative disorders |
| Prognosis | small cleaved cell follicular lymphomas have a slow evolutivity and a median survival of 10 yrs or more; large cell lymphomas have a worse prognosis; the t(14;18) may have little or no prognostic significance, which would be in accordance with its 'oncogenic' role (see below) |
| Cytogenetics |
 | |
| BAC248E24 (BCL2, 18q21, green) cohybridized with PAC PAC 998D24 (14q32.3, red, centromeric to the breakpoint) - Courtesy Mariano Rocchi, Resources for Molecular Cytogenetics | |
| Cytogenetics Morphological | the t(14;18) is well recognized with G-banding, may be overlocked with R-banding; the t(2;18)( p11;q21) and the t(18;22(q21;q11) are rare variants |
| Additional anomalies | found in 90% of cases; complex karyotypes are frequent; by decreasing order, +7, del(6q), +12, + X, + 18, +5, +8, + der(18), + 21 are found in 25 to 10% of cases; +X and del(6q) more frequently in low grade, +7,+8, +der(18), and also the addition of a t(8;14)(q24;q32) more often in high grade NHL |
| Genes involved and Proteins |
| Gene Name | IgH |
| Location | 14q32 |
| Dna / Rna | IGH is composed of IGHV genes, IGHD segments, IGHJ segments, and IGHC genes. |
| Protein | IGH encodes the immunoglobulin heavy chains. They result from the DNA rearrangement (with deletion of the intermediary DNA) of IGHV, IGHD and IGHJ; an additional DNA rearrangement (switch) with constant genes IGHM --> IGHG, IGHA and IGHE can occur. |
| Gene Name | BCL2 |
| Location | 18q21 |
| Dna / Rna | 3 exons; 2 alternative transcripts (a and b) |
| Protein | member of the BCL2 family (with BAX, BCLX,...); contains dimerization domains (BH) and NH domains; BCL2a contains a hydrophobic tail for membrane anchorage; inhibits cell death process through heterodimerization |
| Result of the chromosomal anomaly |
| Description | 5' BCL2 translocated on chromosome 14 near JH (junctions genes of IgH) and C in 3'; the breakpoint in BCL2 is either in the 3' untranslated region of exon 3 (major breakpoint region (MBR) in 70% of cases) or more distal, in 3' of exon 3 (minor cluster region (MCR) in the remaining 30%); illegitimate recombination |
| Description | no fusion protein, but promoter exchange; the immunoglobulin gene enhancer stimulates the expression of BCL2 |
| Oncogenesis | as BCL2 is an apoptosis inhibitor, cell death is delayed, and there is cell accumulation more than real transformation (clones of long living B-cells with t(14;18) may even be seen in the normal population, and with frequency increasing with age) |
| External links |
| Other database | t(14;18)(q32;q21) (IgH/BCL2) | Mitelman database (CGAP - NCBI) | |
| Other database | t(2;18)(p11;q21) | Mitelman database (CGAP - NCBI) | |
| Other database | t(18;22)(q21;q11) | Mitelman database (CGAP - NCBI) | |
| Other database | BCL2/IGH translocation (18/14) (Bari) | ||
| Bibliography |
| Cytogenetic evolution patterns in non-Hodgkin's lymphoma. |
| Johansson B, Mertens F, Mitelman F |
| Blood. 1995 ; 86 (10) : 3905-3914. |
| PMID 7579360 |
| Non-Hodgkin's lymphoma. |
| Maloney DG |
| Current opinion in hematology. 1995 ; 2 (4) : 255-261. |
| PMID 9372005 |
| Cytogenetics of lymphomas: a brief review of its theoretical and practical significance. |
| Donner LR |
| Cancer genetics and cytogenetics. 1997 ; 94 (1) : 20-26. |
| PMID 9078287 |
| Cytogenetic mechanisms in the pathogenesis and progression of follicular lymphoma. |
| Knutsen T |
| Cancer surveys. 1997 ; 30 : 163-192. |
| PMID 9547992 |
| Contributor(s) |
| Written | 05-1998 | Jean-Loup Huret |
| Citation |
| This paper should be referenced as such : |
| Huret JL . t(14;18)(q32;q21) (IgH/BCL2); t(2;18)(p11;q21); t(18;22)(q21;q11). Atlas Genet Cytogenet Oncol Haematol. May 1998 . URL : http://AtlasGeneticsOncology.org/Anomalies/t1418ID2006.html |
This paper is referenced by INIST as such : |
| http://documents.irevues.inist.fr/bitstream/2042/37459/1/05-1998-t1418ID2006.pdf [ Bibliographic record ] |
| © Atlas of Genetics and Cytogenetics in Oncology and Haematology | indexed on : Sat Mar 9 12:38:00 CET 2013 |
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