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Variation in BCL2 protein expression in follicular lymphomas without t(14;18) chromosomal translocations

Masir N, Jones M, Abdul-Rahman F, Florence CS, Mason DY

Pathology, 2012 Apr;44(3):228-33.
PMID: 22406486 DOI: 10.1097/PAT.0b013e3283513fb2

The hallmark of follicular lymphoma is the t(14;18)(q32;q21) chromosomal translocations that lead to deregulation of BCL2 expression in tumour cells. However, not all cases of follicular lymphoma express BCL2, nor is the t(14;18) translocation always present. Follicular lymphomas lacking the BCL2 rearrangement are less well studied with regards to their immunohistochemical and molecular features. This study aims to investigate the BCL2 protein expression pattern in t(14;18) negative follicular lymphomas.

Matched MeSH terms: Chromosomes, Human, Pair 14*; Chromosomes, Human, Pair 18*
Improvement in the detection rate of t(14;18) translocation on paraffin-embedded tissue: a combination approach using PCR and FISH

Shaminie J, Peh SC, Tan MJ

Pathology, 2003 Oct;35(5):414-21.
PMID: 14555386

AIMS: PCR has been the primary method used for the detection of t(14;18) translocation in formalin-fixed, paraffin-embedded tissues. This technique mainly targets the well-characterised breakpoint regions in chromosomes 14 and 18. FISH is now applicable on paraffin tissue sections and has been suggested to be capable of detecting essentially 100% of t(14;18) translocated cases. In this study, we described the application of both PCR and FISH for the detection of t(14;18) translocation.
METHODS: Fifty follicular lymphoma cases were retrieved from the files of the Department of Pathology, University of Malaya Medical Centre (UMMC). Nested PCR amplification of MBR/JH and mcr/JH was performed in these cases, and those cases that did not demonstrate the translocation were subjected to FISH analysis.
RESULTS: Thirty cases (60%) had t(14;18) translocation detected by PCR, 25 (50%) had breakpoint with MBR and five (10%) involved mcr. Twenty cases without detectable t(14;18) translocation by PCR were analysed by FISH. Eleven cases were successfully probed, and four of them showed positive translocation signal.
CONCLUSIONS: The combination of PCR and FISH analysis on paraffin tissue sections for the detection of t(14;18) translocation increases the sensitivity of detection from 60 to 68%. Problems encountered in our FISH analysis on tissue sections impose certain limitations in using this technique for retrospective screening of large number of samples. Therefore, we suggested the application of PCR as the first screening tool on retrospective archival materials, followed by FISH on those PCR-negative cases.

Matched MeSH terms: Chromosomes, Human, Pair 14*; Chromosomes, Human, Pair 18*
BCL2 protein expression in follicular lymphomas with t(14;18) chromosomal translocations

Masir N, Campbell LJ, Goff LK, Jones M, Marafioti T, Cordell J, et al.

Br J Haematol, 2009 Mar;144(5):716-25.
PMID: 19120369 DOI: 10.1111/j.1365-2141.2008.07528.x

The t(14;18)(q32;q21) chromosomal translocation induces BCL2 protein overexpression in most follicular lymphomas. However the expression of BCL2 is not always homogeneous and may demonstrate a variable degree of heterogeneity. This study analysed BCL2 protein expression pattern in 33 cases of t(14;18)-positive follicular lymphomas using antibodies against two different epitopes (i.e. the widely used antibody BCL2/124 and an alternative antibody E17). 16/33 (49%) cases demonstrated strong BCL2 expression. In 10/33 (30%) cases, BCL2 expression was heterogeneous and in some of these, its loss appeared to be correlated with cell proliferation, as indicated by Ki67 expression. Double immunofluorescence labelling confirmed an inverse BCL2/Ki67 relationship, where in 24/28 (86%) cases cellular expression of BCL2 and Ki67 was mutually exclusive. In addition, seven BCL2 'pseudo-negative' cases were identified in which immunostaining was negative with antibody BCL2/124, but positive with antibody E17. Genomic DNA sequencing of these 'pseudo-negative' cases demonstrated eleven mutations in four cases and nine of these were missense mutations. It can be concluded that in follicular lymphomas, despite carrying the t(14;18) translocations, BCL2 protein expression may be heterogeneous and loss of BCL2 could be related to cell proliferation. Secondly, mutations in translocated BCL2 genes appear to be common and may cause BCL2 pseudo-negative immunostaining.

Matched MeSH terms: Chromosomes, Human, Pair 14*; Chromosomes, Human, Pair 18*
Fulltext Familial complex chromosomal rearrangement in a dysmorphic child with global developmental delay

Ngim CF, Keng WT, Ariffin R

Singapore Med J, 2011 Oct;52(10):e206-9.
PMID: 22009409

We report the unusual case of a dysmorphic child with global developmental delay secondary to a familial complex chromosomal rearrangement (CCR). His chromosomal analysis using G-banding and dual colour fluorescence in situ hybridisation with whole chromosome paint revealed a supernumerary marker chromosome as a result of malsegregation of a familial CCR involving chromosomes 7, 12 and 14. The balanced form of this familial CCR was also carried by the patient's mother and maternal grandmother, both of whom had a history of recurrent spontaneous abortions, as well as his maternal uncle, who was infertile. To the best of our knowledge, this is the first reported case of familial CCR involving chromosomes 7, 12 and 14. This case also highlights the importance of chromosomal analysis in children with dysmorphism and developmental delay as well as in adults who suffer from recurrent spontaneous abortions or infertility.

Matched MeSH terms: Chromosomes, Human, Pair 14/genetics
Down syndrome as a result of de novo robertsonian translocation involving chromosome 14 and 21: a case report

Norhasimah, M.M., Ahmad Tarmizi, A.B., Azman, B.A., Zilfalil, B.A., Ankathil, R.

Malaysian Journal of Paediatrics and Child Health, 2007;15(1):46-49.
MyJurnal

Generally, the karyotype profile of Down Syndrome has been reported to be full trisomy 21 in 92% of patients, mosaic trisomy 21 in 4% of patients and translocation involving chromosome 21 in 4% of patients in most of the population groups worldwide. But, karyotype analysis of 149 DS patients at the Human Genome Center, USM, during the past five years revealed that free trisomy accounted for 94.6%, mosaic trisomy 21 for 4.7% and translocation involving chromosome 21 in 0.7% of the Down Syndrome etiology in North East Malaysian population, indicating a low frequency of translocation DS in this region. Here, we report one case of translocation Down Syndrome encountered during karyotype analysis of 149 DS cases. Karyotype showed a robertsonian translocation where an entire extra chromosome 21 was attached to the centromere of one of the chromosome 14, resulting in a derivative chromosome 14 with attached chromosome 21. Karyotype analysis of the parents revealed a normal 46,XY pattern for father and 46,XX pattern for mother indicating that this robertsonian translocation had arisen de novo either prior to or at conception.

Matched MeSH terms: Chromosomes, Human, Pair 14
The pattern and frequency of t(14;18) translocation and immunophenotype in Asian follicular lymphoma

Peh SC, Shaminie J, Tai YC, Tan J, Gan SS

Histopathology, 2004 Nov;45(5):501-10.
PMID: 15500654

Follicular lymphoma is frequently associated with t(14;18)(q32;q21) translocation. This study was undertaken to determine the pattern of Bcl-2, CD10 and Bcl-6 expression in relation to t(14;18) translocation in follicular lymphoma from a cohort of a multi-ethnic Asian population.

Matched MeSH terms: Chromosomes, Human, Pair 14*; Chromosomes, Human, Pair 18*
Pseudonegative BCL2 protein expression in a t(14;18) translocation positive lymphoma cell line: a need for an alternative BCL2 antibody

Masir N, Campbell LJ, Jones M, Mason DY

Pathology, 2010 Apr;42(3):212-6.
PMID: 20350212 DOI: 10.3109/00313021003631296

The t(14;18)(q32;q21) chromosomal translocation induces BCL2 protein expression in most follicular lymphomas. However, a small number of cases lack BCL2 expression despite carrying the t(14;18)(q32;q21) translocation. This study aims to explore the mechanism accounting for the lack of BCL2 protein expression when the t(14;18) translocation is present.

Matched MeSH terms: Chromosomes, Human, Pair 14/genetics
High frequency of germinal centre derivation in diffuse large B cell lymphoma from Asian patients

Shia AK, Gan GG, Jairaman S, Peh SC

J Clin Pathol, 2005 Sep;58(9):962-7.
PMID: 16126878

Recent reports have divided diffuse large B cell lymphoma (DLBCL) into germinal centre B cell-like and activated B cell-like subgroups with implicated differences in prognosis.

Matched MeSH terms: Chromosomes, Human, Pair 14/genetics
Fulltext A case of t(14; 18)-negative follicular lymphoma with atypical immunophenotype: usefulness of immunoarchitecture of Ki67, CD79a and follicular dendritic cell meshwork in making the diagnosis

Wong Y, Abdul-Rahman F, Samsudin AT, Masir N

Malays J Pathol, 2014 Aug;36(2):125-9.
PMID: 25194535 MyJurnal

Follicular lymphoma is characterised by the t(14;18)(q32;q21) chromosomal translocation causing BCL2 protein overexpression. A proportion of follicular lymphomas do not carry the t(14;18) translocation and lacked BCL2 protein expression. We describe a case of a BCL2 protein- and t(14;18)-negative follicular lymphoma that caused diagnostic difficulty. The usefulness of several immunomarkers including Ki67, CD79a and CD21 in aiding the diagnosis is discussed. The patient is a 51-year-old male who presented with gradually enlarging lymphadenopathy. Histopathological examination of the lymph node showed complete architectural effacement by neoplastic follicles containing expanded CD21-positive follicular dendritic cell meshwork. The neoplastic cells expressed pan-B cell markers (CD20, CD79a) and germinal centre marker (BCL6) but not BCL2 and CD10. Of interest are the staining patterns of Ki67 and CD79a. We observed that the Ki67- positive proliferating cells were evenly distributed within the neoplastic follicles without zonation. In addition, CD79a was homogeneously strong within the neoplastic follicles. These staining patterns were distinctly different from that observed in reactive lymphoid follicles. Fluorescent insitu hybridisation (FISH) analysis however showed absence of BCL2 gene rearrangement. Despite the atypical immunophenotype and lack of BCL2 gene rearrangement, the diagnosis of follicular lymphoma was made based on careful observation of the morphology as well as immunoarchitecture of the Ki67, CD79a and CD21 markers.

Matched MeSH terms: Chromosomes, Human, Pair 14