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Liu J, Zhang K, Zhang X, Guan F, Zeng H, Kubo M, Lee P, Candotti F, James LK, Camara NOS, Benlagha K, Lei J, Forsman H, Yang L, Xiao W, Liu Z, Liu C. Immunoglobulin class-switch recombination: Mechanism, regulation, and related diseases. MedComm (Beijing) 2024; 5:e662. [PMID: 39144468 PMCID: PMC11322596 DOI: 10.1002/mco2.662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/30/2024] [Accepted: 06/30/2024] [Indexed: 08/16/2024] Open
Abstract
Maturation of the secondary antibody repertoire requires class-switch recombination (CSR), which switches IgM to other immunoglobulins (Igs), and somatic hypermutation, which promotes the production of high-affinity antibodies. Following immune response or infection within the body, activation of T cell-dependent and T cell-independent antigens triggers the activation of activation-induced cytidine deaminase, initiating the CSR process. CSR has the capacity to modify the functional properties of antibodies, thereby contributing to the adaptive immune response in the organism. Ig CSR defects, characterized by an abnormal relative frequency of Ig isotypes, represent a rare form of primary immunodeficiency. Elucidating the molecular basis of Ig diversification is essential for a better understanding of diseases related to Ig CSR defects and could provide clues for clinical diagnosis and therapeutic approaches. Here, we review the most recent insights on the diversification of five Ig isotypes and choose several classic diseases, including hyper-IgM syndrome, Waldenström macroglobulinemia, hyper-IgD syndrome, selective IgA deficiency, hyper-IgE syndrome, multiple myeloma, and Burkitt lymphoma, to illustrate the mechanism of Ig CSR deficiency. The investigation into the underlying mechanism of Ig CSR holds significant potential for the advancement of increasingly precise diagnostic and therapeutic approaches.
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Affiliation(s)
- Jia‐Chen Liu
- Institute of Hematology, Union Hospital, Tongji Medical College, Huazhong University of Science and TechnologyWuhanChina
- Department of Pathogen BiologySchool of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and TechnologyWuhanHubeiChina
| | - Ke Zhang
- Department of Pathogen BiologySchool of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and TechnologyWuhanHubeiChina
| | - Xu Zhang
- Department of RespiratoryThe First Affiliated Hospital of Yangtze UniversityJingzhouChina
| | - Fei Guan
- Department of Pathogen BiologySchool of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and TechnologyWuhanHubeiChina
| | - Hu Zeng
- Department of ImmunologyMayo Clinic College of Medicine and ScienceRochesterUSA
| | - Masato Kubo
- Laboratory for Cytokine Regulation, Center for Integrative Medical Science (IMS), RIKEN Yokohama InstituteYokohamaJapan
| | - Pamela Lee
- Department of Paediatrics and Adolescent MedicineLKS Faculty of MedicineThe University of Hong KongHong KongChina
| | - Fabio Candotti
- Division of Immunology and AllergyLausanne University Hospital and University of LausanneLausanneSwitzerland
| | | | | | - Kamel Benlagha
- Institut de Recherche Saint‐LouisUniversité de ParisParisFrance
| | - Jia‐Hui Lei
- Department of Pathogen BiologySchool of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and TechnologyWuhanHubeiChina
| | - Huamei Forsman
- Department of Rheumatology and Inflammation ResearchInstitute of Medicine, Sahlgrenska Academy, University of GothenburgGothenburgSweden
| | - Lu Yang
- Department of Pathogen BiologySchool of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and TechnologyWuhanHubeiChina
| | - Wei Xiao
- Department of RespiratoryThe First Affiliated Hospital of Yangtze UniversityJingzhouChina
| | - Zheng Liu
- Department of Otolaryngology‐Head and Neck SurgeryTongji Hospital, Tongji Medical College, HuazhongUniversity of Science and TechnologyWuhanChina
| | - Chao‐Hong Liu
- Department of Pathogen BiologySchool of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, Huazhong University of Science and TechnologyWuhanHubeiChina
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2
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Paradoxical role of Id proteins in regulating tumorigenic potential of lymphoid cells. Front Med 2018; 12:374-386. [PMID: 30043222 DOI: 10.1007/s11684-018-0652-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 06/26/2018] [Indexed: 12/11/2022]
Abstract
A family of transcription factors known as Id proteins, or inhibitor of DNA binding and differentiation, is capable of regulating cell proliferation, survival and differentiation, and is often upregulated in multiple types of tumors. Due to their ability to promote self-renewal, Id proteins have been considered as oncogenes, and potential therapeutic targets in cancer models. On the contrary, certain Id proteins are reported to act as tumor suppressors in the development of Burkitt's lymphoma in humans, and hepatosplenic and innate-like T cell lymphomas in mice. The contexts and mechanisms by which Id proteins can serve in such contradictory roles to determine tumor outcomes are still not well understood. In this review, we explore the roles of Id proteins in lymphocyte development and tumorigenesis, particularly with respect to inhibition of their canonical DNA binding partners known as E proteins. Transcriptional regulation by E proteins, and their antagonism by Id proteins, act as gatekeepers to ensure appropriate lymphocyte development at key checkpoints. We re-examine the derailment of these regulatory mechanisms in lymphocytes that facilitate tumor development. These mechanistic insights can allow better appreciation of the context-dependent roles of Id proteins in cancers and improve considerations for therapy.
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Clinical utility of recently identified diagnostic, prognostic, and predictive molecular biomarkers in mature B-cell neoplasms. Mod Pathol 2017; 30:1338-1366. [PMID: 28664939 DOI: 10.1038/modpathol.2017.58] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 04/25/2017] [Accepted: 04/26/2017] [Indexed: 12/18/2022]
Abstract
Genomic profiling studies have provided new insights into the pathogenesis of mature B-cell neoplasms and have identified markers with prognostic impact. Recurrent mutations in tumor-suppressor genes (TP53, BIRC3, ATM), and common signaling pathways, such as the B-cell receptor (CD79A, CD79B, CARD11, TCF3, ID3), Toll-like receptor (MYD88), NOTCH (NOTCH1/2), nuclear factor-κB, and mitogen activated kinase signaling, have been identified in B-cell neoplasms. Chronic lymphocytic leukemia/small lymphocytic lymphoma, diffuse large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma, Burkitt lymphoma, Waldenström macroglobulinemia, hairy cell leukemia, and marginal zone lymphomas of splenic, nodal, and extranodal types represent examples of B-cell neoplasms in which novel molecular biomarkers have been discovered in recent years. In addition, ongoing retrospective correlative and prospective outcome studies have resulted in an enhanced understanding of the clinical utility of novel biomarkers. This progress is reflected in the 2016 update of the World Health Organization classification of lymphoid neoplasms, which lists as many as 41 mature B-cell neoplasms (including provisional categories). Consequently, molecular genetic studies are increasingly being applied for the clinical workup of many of these neoplasms. In this review, we focus on the diagnostic, prognostic, and/or therapeutic utility of molecular biomarkers in mature B-cell neoplasms.
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Rowe M, Fitzsimmons L, Bell AI. Epstein-Barr virus and Burkitt lymphoma. CHINESE JOURNAL OF CANCER 2014; 33:609-19. [PMID: 25418195 PMCID: PMC4308657 DOI: 10.5732/cjc.014.10190] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 11/06/2014] [Indexed: 12/12/2022]
Abstract
In 1964, a new herpesvirus, Epstein-Barr virus (EBV), was discovered in cultured tumor cells derived from a Burkitt lymphoma (BL) biopsy taken from an African patient. This was a momentous event that reinvigorated research into viruses as a possible cause of human cancers. Subsequent studies demonstrated that EBV was a potent growth-transforming agent for primary B cells, and that all cases of BL carried characteristic chromosomal translocations resulting in constitutive activation of the c-MYC oncogene. These results hinted at simple oncogenic mechanisms that would make Burkitt lymphoma paradigmatic for cancers with viral etiology. In reality, the pathogenesis of this tumor is rather complicated with regard to both the contribution of the virus and the involvement of cellular oncogenes. Here, we review the current understanding of the roles of EBV and c-MYC in the pathogenesis of BL and the implications for new therapeutic strategies to treat this lymphoma.
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Affiliation(s)
- Martin Rowe
- School of Cancer Sciences, University of Bir-mingham CMDS, Vincent Drive, Edgbaston, Birmingham, B15 2TT, UK.
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Sklyar IV, Iarovaia OV, Lipinski M, Vassetzky YS. Translocations affecting human immunoglobulin heavy chain locus. ACTA ACUST UNITED AC 2014. [DOI: 10.7124/bc.000886] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- I. V. Sklyar
- CNRS UMR8126, Paris-Sud University, Gustave Roussy Institute
- Institute of Gene Biology, Russian Academy of Sciences
- LIA 1066 French-Russian Joint Cancer Research Laboratory
| | - O. V. Iarovaia
- Institute of Gene Biology, Russian Academy of Sciences
- LIA 1066 French-Russian Joint Cancer Research Laboratory
| | - M. Lipinski
- CNRS UMR8126, Paris-Sud University, Gustave Roussy Institute
- LIA 1066 French-Russian Joint Cancer Research Laboratory
| | - Y. S. Vassetzky
- Institute of Gene Biology, Russian Academy of Sciences
- LIA 1066 French-Russian Joint Cancer Research Laboratory
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Aquino G, Marra L, Cantile M, De Chiara A, Liguori G, Curcio MP, Sabatino R, Pannone G, Pinto A, Botti G, Franco R. MYC chromosomal aberration in differential diagnosis between Burkitt and other aggressive lymphomas. Infect Agent Cancer 2013; 8:37. [PMID: 24079473 PMCID: PMC3850004 DOI: 10.1186/1750-9378-8-37] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 09/17/2013] [Indexed: 11/10/2022] Open
Abstract
Myc oncogenetic deregulation is abundantly described in several solid human cancer and lymphomas. Particularly, Burkitt's lymphoma belongs to the family of B Non Hodgkin aggressive lymphomas. Although it is morphologically characterized, immunophenotypic and cytogenetic diagnosis remains complex. In 2008, the WHO has introduced a new diagnostic class of aggressive B-cell lymphomas with features intermediate between BL and DLBCL. This diagnostic class represents a temporary container of aggressive B-cell lymphomas, not completely belonging to the BL and DLBCL categories. The importance of establishing a correct diagnosis would allow a better prognostic classification and a better therapeutic approach. In this review, we summarize the main diagnostic approaches necessary for appropriate diagnoses and we emphasize the importance of cytogenetic analysis of the oncogene Myc in the histopathological diagnosis and the prognostic/predictive stratification. In this contest, Myc represents the more involved gene in the development of these lymphomas. Therefore, we analyze the genetic aberrations causing its over-expression and the concomitant deregulation of molecular pathways related to it. We also propose a FISH approach useful in the diagnosis of these lymphomas.
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Affiliation(s)
- Gabriella Aquino
- Pathology Unit, "Istituto Nazionale Tumori Fondazione G. Pascale" - Irccs, Naples, Italy
| | - Laura Marra
- Pathology Unit, "Istituto Nazionale Tumori Fondazione G. Pascale" - Irccs, Naples, Italy
| | - Monica Cantile
- Pathology Unit, "Istituto Nazionale Tumori Fondazione G. Pascale" - Irccs, Naples, Italy
| | - Annarosaria De Chiara
- Pathology Unit, "Istituto Nazionale Tumori Fondazione G. Pascale" - Irccs, Naples, Italy
| | - Giuseppina Liguori
- Pathology Unit, "Istituto Nazionale Tumori Fondazione G. Pascale" - Irccs, Naples, Italy
| | - Maria Pia Curcio
- Pathology Unit, "Istituto Nazionale Tumori Fondazione G. Pascale" - Irccs, Naples, Italy
| | - Rocco Sabatino
- Pathology Unit, "Istituto Nazionale Tumori Fondazione G. Pascale" - Irccs, Naples, Italy
| | - Giuseppe Pannone
- Medicine and Surgery Department, Foggia University, Foggia, Italy
| | - Antonio Pinto
- Haematology Unit, "Istituto Nazionale Tumori Fondazione G. Pascale" - Irccs, Naples, Italy
| | - Gerardo Botti
- Pathology Unit, "Istituto Nazionale Tumori Fondazione G. Pascale" - Irccs, Naples, Italy
| | - Renato Franco
- Pathology Unit, "Istituto Nazionale Tumori Fondazione G. Pascale" - Irccs, Naples, Italy
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Laurent C, Guérin M, Frenois FX, Thuries V, Jalabert L, Brousset P, Valmary-Degano S. Whole-slide imaging is a robust alternative to traditional fluorescent microscopy for fluorescence in situ hybridization imaging using break-apart DNA probes. Hum Pathol 2013; 44:1544-55. [PMID: 23517924 DOI: 10.1016/j.humpath.2012.12.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 11/28/2012] [Accepted: 12/06/2012] [Indexed: 11/19/2022]
Abstract
Fluorescence in situ hybridization is an indispensable technique used in routine pathology and for theranostic purposes. Because fluorescence in situ hybridization techniques require sophisticated microscopic workstations and long procedures of image acquisition with sometimes subjective and poorly reproducible results, we decided to test a whole-slide imaging system as an alternative approach. In this study, we used the latest generation of Pannoramic 250 Flash digital microscopes (P250 Flash digital microscopes; 3DHISTECH, Budapest, Hungary) to digitize fluorescence in situ hybridization slides of diffuse large B cells lymphoma cases for detecting MYC rearrangement. The P250 Flash digital microscope was found to be precise with better definition of split signals in cells containing MYC rearrangement with fewer truncated signals as compared to traditional fluorescence microscopy. This digital technique is easier thanks to the preview function, which allows almost immediate identification of the tumor area, and the panning and zooming functionalities as well as a shorter acquisition time. Moreover, fluorescence in situ hybridization analyses using the digital technique appeared to be more reproducible between pathologists. Finally, the digital technique also allowed prolonged conservation of photos. In conclusion, whole-slide imaging technologies represent rapid, robust, and highly sensitive methods for interpreting fluorescence in situ hybridization slides with break-apart probes. In addition, these techniques offer an easier way to interpret the signals and allow definitive storage of the images for pathology expert networks or e-learning databases.
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Affiliation(s)
- Camille Laurent
- INSERM, U.563, Centre de Physiopathologie de Toulouse Purpan, Toulouse, F-31300 France.
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TGF-β-induced apoptosis of B-cell lymphoma Ramos cells through reduction of MS4A1/CD20. Oncogene 2012; 32:2096-106. [PMID: 22665052 DOI: 10.1038/onc.2012.219] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Transforming growth factor-β (TGF-β) exhibits growth inhibitory effects on various types of tumor cells, including B-cell lymphoma cells. In the present study, the role of TGF-β in the survival of Epstein-Barr virus-negative B-cell lymphoma Ramos cells was investigated. As TGF-β-induced apoptosis of Ramos cells in vitro and in vivo, we attempted to identify novel target gene(s) responsible for their survival. Oligonucleotide microarray analysis and chromatin immunoprecipitation revealed that Smad proteins directly regulated the transcription of membrane-spanning 4-domains, subfamily A, member 1 (MS4A1), also known as CD20, in Ramos cells upon TGF-β stimulation. In addition, immunohistochemical analysis using clinical samples from B-cell lymphoma patients showed an inverse correlation between the expression of MS4A1/CD20 and phosphorylation of Smad3. Although knockdown of MS4A1/CD20 in Ramos cells resulted in an increase of apoptotic cells, Ramos cells stably expressing MS4A1/CD20 were resistant to TGF-β-induced apoptosis. This suggests that MS4A1/CD20 is responsible for TGF-β-induced apoptosis of B-cell lymphoma cells. Moreover, downregulation of MS4A1/CD20 by TGF-β attenuated the effects of the monoclonal anti-MS4A1/CD20 antibody, rituximab, on Ramos cells. Our findings suggest that the sensitivity of B-cell lymphoma cells to rituximab may be affected by TGF-β signaling.
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Kikuchi K, Inoue H, Miyazaki Y, Ide F, Matsuki E, Shigematu H, Okamoto S, Sakashita H, Kusama K. Adult sporadic burkitt lymphoma of the oral cavity: a case report and literature review. J Oral Maxillofac Surg 2012; 70:2936-43. [PMID: 22520562 DOI: 10.1016/j.joms.2012.02.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 02/15/2012] [Accepted: 02/15/2012] [Indexed: 02/04/2023]
Affiliation(s)
- Kentaro Kikuchi
- Division of Pathology, Department of Diagnostic & Therapeutic Sciences, Meikai University School of Dentistry, Saitama, Japan.
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10
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Grey zone lymphomas: lymphomas with intermediate features. Adv Hematol 2012; 2012:460801. [PMID: 22548066 PMCID: PMC3324130 DOI: 10.1155/2012/460801] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 01/10/2012] [Accepted: 01/20/2012] [Indexed: 01/24/2023] Open
Abstract
The current classification of lymphoid neoplasms is based on clinical information, morphology, immunophenotype, and molecular genetic characteristics. Despite technical and scientific progress, some aggressive B-cell lymphomas with features overlapping between two different types of lymphomas remain difficult to classify. The updated 2008 World Health Organization (WHO) classification of Tumours of the Hematopoietic and Lymphoid Tissues has addressed this problem by creation of two new provisional categories of B-cell lymphomas, unclassifiable; one with features intermediate between diffuse large B-cell lymphoma and classical Hodgkin lymphoma and the second with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma. We review here the diagnostic criteria of these two provisional entities and discuss new scientific findings in light of the 2008 WHO classification.
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Abstract
Burkitt's lymphoma is a highly aggressive B-cell non-Hodgkin lymphoma and is the fastest growing human tumour. The disease is associated with Epstein-Barr virus and was one of the first tumours shown to have a chromosomal translocation that activates an oncogene (c-MYC). Burkitt's lymphoma is the most common childhood cancer in areas where malaria is holoendemic. The incidence is very high in immunosuppressed patients in non-endemic areas, especially when associated with HIV infection. Outcome with intensive chemotherapy has improved and is now excellent in children, but the prognosis is poor in elderly adults. The success of intensive treatment relies on good supportive care. The therapy offered in oncology units in low-income countries is not as aggressive as in centres in high-income countries and outcomes are less successful. Adjuvant monoclonal antibody therapy with rituximab shows promise for improved outcomes and reduced toxic effects in the future.
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de Jong D, Balagué Ponz O. The molecular background of aggressive B cell lymphomas as a basis for targeted therapy. J Pathol 2010; 223:274-82. [PMID: 21125680 DOI: 10.1002/path.2807] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 10/04/2010] [Accepted: 10/09/2010] [Indexed: 12/15/2022]
Abstract
In contrast to classifications for the majority of solid tumours, non-Hodgkin's lymphomas have been defined on the basis of their genetic alterations for many years, providing a biologically highly relevant classification. However, for aggressive B cell lymphomas, which unfortunately is the most prevalent group of lymphomas in adults, the stratification is less optimal. Gene expression profiling, analyses of chromosomal alterations and functional assays have been instrumental in dissecting these tumours to support the distinction of essentially different diseases, such as diffuse large B cell lymphoma and Burkitt's lymphoma, and now start to identify the dominant driving oncogenetic pathways that may serve as rational therapeutic targets in this essentially heterogeneous group. In this review, the molecular background and the consequences of the molecular alterations in the context of the consequences for treatment in aggressive B cell lymphoma are discussed.
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Affiliation(s)
- Daphne de Jong
- Department of Pathology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
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Guikema JEJ, Schuuring E, Kluin PM. Structure and consequences of IGH switch breakpoints in Burkitt lymphoma. J Natl Cancer Inst Monogr 2008:32-6. [PMID: 18647999 DOI: 10.1093/jncimonographs/lgn020] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The t(8;14) MYC/IGH breakpoint is the hallmark translocation of human Burkitt lymphoma (BL). The translocation breakpoint most often involves the immunoglobulin heavy-chain switch regions and is thought to be brought about by an aberrant class switch recombination (CSR) event. During CSR in normal germinal center B cells, DNA double-stranded breaks are introduced in Smu and one of the downstream switch regions (Sgamma, Salpha, or Sepsilon) that are juxtaposed and ligated to form the switch junction, with deletion of the intervening DNA. In contrast, aberrant switch recombination in BL exclusively involves only one switch region, resulting in a perfect reciprocal translocation. A functional consequence of this type of translocation is that IgM expression from the chromosome affected by the translocation is not necessarily disrupted.
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Affiliation(s)
- Jeroen E J Guikema
- Department of Pathology and Laboratory Medicine, University Medical Center Groningen, The Netherlands.
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14
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Ruminy P, Jardin F, Penther D, Picquenot JM, Parmentier F, Buchonnet G, Bertrand P, Tilly H, Bastard C. Recurrent disruption of the Imu splice donor site in t(14;18) positive lymphomas: a potential molecular basis for aberrant downstream class switch recombination. Genes Chromosomes Cancer 2007; 46:735-44. [PMID: 17455255 DOI: 10.1002/gcc.20453] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
t(14;18) positive lymphomas are mature germinal center B-cell neoplasms. In agreement with this cellular origin, most have somatically mutated immunoglobulin variable genes and the IGH@ locus has almost always been reorganized by class switch recombination (CSR). However, contrasting with normal B-cells, a majority of cases still express an IgM while the constant genes are normally rearranged only on the non-productive allele. Concurrently, aberrant intra-allelic junctions involving downstream switch regions, with a lack of engagement of the switch mu (Smu), often accumulate on the functional alleles, suggesting some recurrent CSR perturbation during the onset of the disease. To clarify these surprising observations, we addressed the accessibility of the Smu to the CSR machinery in a large series of patients by characterizing the mutations that are expected to accumulate at this place upon CSR activation. Our data indicate that the Smu is mutated in a large majority of cases, often on both alleles, indicating that these cells usually reach a differentiation stage where CSR is activated and where this region remains accessible. Interestingly, we also identified a significant cluster of mutations at the splicing donor site of the first exon of the Smu germline transcripts, on the functional allele. This location suggests a possible relation with CSR perturbations in lymphoma and the clustering points to a probable mechanism of selection. In conclusion, our data suggest that an acquired mutation at the splicing donor site of the Smu transcripts may participate in the selection of lymphoma cells and play a significant role during the onset of the disease.
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MESH Headings
- Chromosomes, Human, Pair 14
- Chromosomes, Human, Pair 18
- Humans
- Immunoglobulin Class Switching/genetics
- Immunoglobulin Switch Region
- Lymphoma, B-Cell/etiology
- Lymphoma, B-Cell/genetics
- Lymphoma, B-Cell/immunology
- Lymphoma, B-Cell/pathology
- Mutation
- RNA Splice Sites/genetics
- Sequence Analysis, DNA
- Translocation, Genetic
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Affiliation(s)
- Philippe Ruminy
- Groupe d'Etude des Proliférations Lymphoïdes, Centre Henri Becquerel, INSERM U614, IFR23, 76000 Rouen, France.
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