+12 or trisomy 12

2000-05-01   Lucienne Michaux 

1.Department of Hematology and Center for Human Genetics Cliniques Universitaires Saint Luc Avenue Hippocrate 10 1200 Brussels, Belgium

Clinics and Pathology


B-cell chronic lymphocytic leukemia (B-CLL)

Phenotype stem cell origin

virgin CD5+ recirculating B-cell; the classical CLL phenotype is CD5+, CD23+, CD22-, CD79a-, FMC7-, sIg weak; trisomy 12 is more often observed in CLL with morphologically and immunologically atypical cells, displaying CD5 negativity or FMC7 positivity and strong surface immunoglobulin staining; trisomy 12 is present in proliferating cells and seems to be associated with the absence of mutation of the Ig variable region genes


trisomy 12 is found in one third of cytogenetically abnormal CLLs by conventional karyotype, and in about 12-54% of cases when interphase FISH is used


a significant difference comparing the therapy-free interval of patients with +12 and patients with other anomalies was found; this observation was repeatedly confirmed; however an adverse impact of +12 on survival could not be demonstrated until the IWCLL compiled karyotype and survival data from more than 400 patients and showed a median survival of 5.4 years versus 8.6 years versus 14 years in patients with +12 versus another single abnormality versus a normal karyotype, respectively; the preliminary results on a large series of patients analyzed by interphase FISH showed that +12 and 14q+ changes are associated with shorter survival times, compared to patients with 13q abnormalities and normal karyotypes; however prospective data are needed to further assess the prognostic value of this cytogenetic change

Phenotype stem cell origin

lack of specificity for a particular immunophenotype


no data are available concerning the prognostic significance of +12, except in one series of mantle cell lymphomas in which it was the only single cytogenetic parameter associated with poor prognosis


Pubmed IDLast YearTitleAuthors
79937921994Trisomy 12 is uncommon in typical chronic lymphocytic leukaemias.Criel A et al
34751651987Origin of trisomy 12 in B-cell chronic lymphocytic leukemia.Crossen PE et al
99491811999Cytogenetic profile of lymphoma of follicle mantle lineage: correlation with clinicobiologic features.Cuneo A et al
100237801999Chromosome aberrations in B-cell chronic lymphocytic leukemia: reassessment based on molecular cytogenetic analysis.Döhner H et al
93315661997FISH identifies different types of duplications with 12q13-15 as the commonly involved segment in B-cell lymphoproliferative malignancies characterized by partial trisomy 12.Dierlamm J et al
25861801989Molecular analyses of chromosome 12 in chronic lymphocytic leukemia.Einhorn S et al
79472551994Trisomy 12 in B-cell chronic lymphocytic leukaemia: assessment of lineage restriction by simultaneous analysis of immunophenotype and genotype in interphase cells by fluorescence in situ hybridization.Garcìa-Marco J et al
104777131999Unmutated Ig V(H) genes are associated with a more aggressive form of chronic lymphocytic leukemia.Hamblin TJ et al
86097311995Cytogenetic analysis of B cell chronic lymphoid leukemias classified according to morphologic and immunophenotypic (FAB) criteria.Hernandez JM et al
86030041996Trisomy 12 defines a group of CLL with atypical morphology: correlation between cytogenetic, clinical and laboratory features in 544 patients.Matutes E et al
76871641993Trisomy 12 in chronic lymphocytic leukemia detected by fluorescence in situ hybridization: analysis by stage, immunophenotype, and morphology.Que TH et al
66064861984Clinical significance of cytogenetic findings in untreated patients with B-cell chronic lymphocytic leukemia.Sadamori N et al



trisomy 12 is the most common cytogenetic change in chronic lymphocytic leukemia (CLL); however, it has also been observed in other subtypes of B-cell lymphoproliferative disorders, where it is not seldomly a secondary change
Atlas Image
Trisomy 12 Top: trisomy 12 R-banding and FISH - Courtesy Hossein Mossafa. Bottom: Detection of trisomy 12 using fluorescence in situ hybridization with the Vysis SpectrumGreen-labeled probe specific for the alpha satellite (centromeric) region, 12p11.1-q11 and with LSI D13S319 SpectrumOrange/CEP 12 SpectrumGreen probes (Abbott Molecular, US) showing 3 copies of chromosomes 12 (green signals) - Courtesy Adriana Zamecnikova.


Lucienne Michaux

+12 or trisomy 12

Atlas Genet Cytogenet Oncol Haematol. 2000-05-01

Online version: http://atlasgeneticsoncology.org/haematological/2024/+12-or-trisomy-12

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