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Bibas M, Sarosiek S, Castillo JJ. Waldenström Macroglobulinemia - A State-of-the-Art Review: Part 1: Epidemiology, Pathogenesis, Clinicopathologic Characteristics, Differential Diagnosis, Risk Stratification, and Clinical Problems. Mediterr J Hematol Infect Dis 2024; 16:e2024061. [PMID: 38984103 PMCID: PMC11232678 DOI: 10.4084/mjhid.2024.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Accepted: 06/19/2024] [Indexed: 07/11/2024] Open
Abstract
Waldenström macroglobulinemia (WM) is an infrequent variant of lymphoma, classified as a B-cell malignancy identified by the presence of IgM paraprotein, infiltration of clonal, small lymphoplasmacytic B cells in the bone marrow, and the MYD88 L265P mutation, which is observed in over 90% of cases. The direct invasion of the malignant cells into tissues like lymph nodes and spleen, along with the immune response related to IgM, can also lead to various health complications, such as cytopenias, hyperviscosity, peripheral neuropathy, amyloidosis, and Bing-Neel syndrome. Chemoimmunotherapy has historically been considered the preferred treatment for WM, wherein the combination of rituximab and nucleoside analogs, alkylating drugs, or proteasome inhibitors has exhibited notable efficacy in inhibiting tumor growth. Recent studies have provided evidence that Bruton Tyrosine Kinase inhibitors (BTKI), either used independently or in conjunction with other drugs, have been shown to be effective and safe in the treatment of WM. The disease is considered to be non-curable, with a median life expectancy of 10 to 12 years.
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Affiliation(s)
- Michele Bibas
- Department of Clinical Research, Hematology. National Institute for Infectious Diseases "Lazzaro Spallanzani" IRCSS Rome Italy
| | - Shayna Sarosiek
- Bing Center for Waldenström's Macroglobulinemia, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA
| | - Jorge J Castillo
- Bing Center for Waldenström's Macroglobulinemia, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA
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Waldenström Macroglobulinemia: Mechanisms of Disease Progression and Current Therapies. Int J Mol Sci 2022; 23:ijms231911145. [PMID: 36232447 PMCID: PMC9569492 DOI: 10.3390/ijms231911145] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/12/2022] [Accepted: 09/20/2022] [Indexed: 11/17/2022] Open
Abstract
Waldenström macroglobulinemia is an indolent, B-cell lymphoma without a known cure. The bone marrow microenvironment and cytokines both play key roles in Waldenström macroglobulinemia (WM) tumor progression. Only one FDA-approved drug exists for the treatment of WM, Ibrutinib, but treatment plans involve a variety of drugs and inhibitors. This review explores avenues of tumor progression and targeted drug therapy that have been investigated in WM and related B-cell lymphomas.
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Matissek SJ, Han W, Karbalivand M, Sayed M, Reilly BM, Mallat S, Ghazal SM, Munshi M, Yang G, Treon SP, Walker SR, Elsawa SF. Epigenetic targeting of Waldenström macroglobulinemia cells with BET inhibitors synergizes with BCL2 or histone deacetylase inhibition. Epigenomics 2020; 13:129-144. [PMID: 33356554 DOI: 10.2217/epi-2020-0189] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Aim: Waldenström macroglobulinemia (WM) is a low-grade B-cell lymphoma characterized by overproduction of monoclonal IgM. To date, there are no therapies that provide a cure for WM patients, and therefore, it is important to explore new therapies. Little is known about the efficiency of epigenetic targeting in WM. Materials & methods: WM cells were treated with BET inhibitors (JQ1 and I-BET-762) and venetoclax, panobinostat or ibrutinib. Results: BET inhibition reduces growth of WM cells, with little effect on survival. This finding was enhanced by combination therapy, with panobinostat (LBH589) showing the highest synergy. Conclusion: Our studies identify BET inhibitors as effective therapy for WM, and these inhibitors can be enhanced in combination with BCL2 or histone deacetylase inhibition.
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Affiliation(s)
- Stephan J Matissek
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Weiguo Han
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Mona Karbalivand
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Mohamed Sayed
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Brendan M Reilly
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Shayna Mallat
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Shimaa M Ghazal
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Manit Munshi
- Bing Center for Waldenström Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Guang Yang
- Bing Center for Waldenström Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Steven P Treon
- Bing Center for Waldenström Macroglobulinemia, Dana-Farber Cancer Institute, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Sarah R Walker
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
| | - Sherine F Elsawa
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH, 03824, USA
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Ahn A, Park CJ, Cho YU, Jang S, Seo EJ, Lee JH, Yoon DH, Suh C. Clinical, Laboratory, and Bone Marrow Findings of 31 Patients With Waldenström Macroglobulinemia. Ann Lab Med 2020; 40:193-200. [PMID: 31858758 PMCID: PMC6933056 DOI: 10.3343/alm.2020.40.3.193] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 05/29/2019] [Accepted: 10/24/2019] [Indexed: 01/27/2023] Open
Abstract
Background Waldenström macroglobulinemia (WM) is a subset of lymphoplasmacytic lymphoma (LPL) with bone marrow (BM) involvement and an IgM monoclonal gammopathy of any level. We aimed to identify the clinical, laboratory, and BM findings of patients with WM and to evaluate the usefulness of CD154 for the diagnosis and prognosis of WM. Methods We reviewed the medical records and BM studies and/or flow cytometric immunotyping of 31 patients with untreated WM. Semiquantitative immunohistochemistry (CD20, CD138, tryptase, and CD154) of BM was performed. Results Only six patients presented with symptoms of hyperviscosity syndrome. Eleven patients had solid cancer and/or another hematologic malignancy. Mast cells (MC) increased in all samples, with some in close contact with tumor cells. Tryptase-positive MC (17.1/ high-power fields [HPF], 1.2–72.0/HPF) and CD154-positive MC (8.6/HPF, 0.1–31.1/HPF) were observed. The high CD154-positive MC (≥8.6/HPF) group showed a lower overall five-year survival rate than the low CD154-positive MC (<8.6/HPF) group (71.9% vs. 100.0%; P=0.012). Flow cytometric immunophenotyping of BM aspirates showed increased B lymphocytes and plasma cells with a normal phenotype (CD138+/CD38+/CD19+/CD45+/CD56−). Conclusions Approximately one third of WM patients showed other malignancies and all patients had increased MC. Immunohistochemistry and flow cytometric immunophenotyping are useful for diagnosing WM, and increased CD154-positive MC can indicate poor prognosis.
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Affiliation(s)
- Ari Ahn
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Chan Jeoung Park
- Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
| | - Young Uk Cho
- Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
| | - Seongsoo Jang
- Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
| | - Eul Ju Seo
- Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
| | - Jung Hee Lee
- Department of Internal Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
| | - Dok Hyun Yoon
- Department of Internal Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
| | - Cheolwon Suh
- Department of Internal Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
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Soluble PD-1 ligands regulate T-cell function in Waldenstrom macroglobulinemia. Blood Adv 2019; 2:1985-1997. [PMID: 30104397 DOI: 10.1182/bloodadvances.2018021113] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/18/2018] [Indexed: 01/11/2023] Open
Abstract
Although immune checkpoint molecules regulate the progression of certain cancers, their significance in malignant development of Waldenstrom macroglobulinemia (WM), an incurable low-grade B-cell lymphoma, remains unknown. Recently, cytokines in the bone marrow (BM) microenvironment are shown to contribute to the pathobiology of WM. Here, we investigated the impact of cytokines, including interleukin-6 (IL-6) and IL-21, on immune regulation and particularly on the programmed death-1 (PD-1) and its ligands PD-L1 and PD-L2. We showed that IL-21, interferon γ, and IL-6 significantly induced PD-L1 and PD-L2 gene expression in WM cell lines. Increased PD-L1 and PD-L2 messenger RNA was also detected in patients' BM cells. Patients' nonmalignant BM cells, including T cells and monocytes, showed increased PD-L1, but minimal or undetectable PD-L2 surface expression. There was also very modest PD-L1 and PD-L2 surface expression by malignant WM cells, suggesting that ligands are cleaved from the cell surface. Levels of soluble ligands were higher in patients' BM plasma and blood serum than controls. Furthermore, IL-21 and IL-6 increased secreted PD-L1 in the culture media of WM cell lines, implying that elevated levels of soluble PD-1 ligands are cytokine mediated. Soluble PD-1 ligands reduced T-cell proliferation, phosphorylated extracellular signal-regulated kinase and cyclin A levels, mitochondrial adenosine triphosphate production, and spare respiratory capacity. In conclusion, we identify that soluble PD-1 ligands are elevated in WM patients and, in addition to surface-bound ligands in WM BM, could regulate T-cell function. Given the capability of secreted forms to be bioactive at distant sites, soluble PD-1 ligands have the potential to promote disease progression in WM.
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Raimbault A, Machherndl-Spandl S, Itzykson R, Clauser S, Chapuis N, Mathis S, Lauf J, Alary AS, Burroni B, Kosmider O, Fontenay M, Béné MC, Durrieu F, Bettelheim P, Bardet V. CD13 expression in B cell malignancies is a hallmark of plasmacytic differentiation. Br J Haematol 2018; 184:625-633. [PMID: 30198568 DOI: 10.1111/bjh.15584] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Accepted: 07/24/2018] [Indexed: 11/30/2022]
Abstract
The diagnosis of Waldenström Macroglobulinaemia (WM)/lymphoplasmacytic lymphoma (LPL) remains one of exclusion because other B-cell lymphoproliferative disorders (B-LPD), such as marginal zone lymphoma (MZL), can fulfil similar criteria, including MYD88 L265P mutation. It has been suggested that expression of the myeloid marker CD13 (also termed ANPEP) is more frequent in LPL than in other B-LPD and has also been described on normal and malignant plasma cells. Here, CD13 expression was tested in a cohort of 1037 B-LPD patients from 3 centres by flow cytometry. The percentage of CD13-expressing cells was found to be variable among B-LPD but significantly higher in WM/LPL (median 31% vs. 0% in non-WM/LPL, P < 0·001). In multivariate linear regression, CD13 expression remained significantly associated with a diagnosis of WM/LPL (P < 0·001). A cut-off value of 2% of CD19+ cells co-expressing CD13 yielded the best diagnostic performance for WM/LPL assertion. This was further improved by association with the presence or absence of IgM paraprotein. Finally, given that previously published transcriptomic data revealed no difference in CD13 (also termed ANPEP) mRNA between normal and pathological B-cells, the hypothesis of some post-transcriptional regulation must be favoured. These results suggest that testing for CD13 expression in routine flow cytometry panels could help to discriminate WM/LPL from other B-LPD.
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Affiliation(s)
- Anna Raimbault
- Service d'Hématologie Biologique, Hôpitaux Universitaires Paris Centre, Université Paris Descartes, Paris, France
| | - Sigrid Machherndl-Spandl
- Department of Haematology, Internal Oncology and Stem Cell Transplantation, Ordensklinikum Linz Elisabethinen Hospital, Linz, Austria
| | - Raphaël Itzykson
- Service d'Hématologie Clinique, Hôpitaux Universitaires Saint Louis, Lariboisière, Fernand Widal, Université Paris Diderot, Paris, France
| | - Sylvain Clauser
- Service d'Hématologie-Immunologie-Transfusion, Hôpitaux Universitaires Paris Ile De France Ouest, Université Versailles Saint Quentin, Boulogne, France
| | - Nicolas Chapuis
- Service d'Hématologie Biologique, Hôpitaux Universitaires Paris Centre, Université Paris Descartes, Paris, France
| | - Stéphanie Mathis
- Service d'Hématologie Biologique, Hôpitaux Universitaires Paris Centre, Université Paris Descartes, Paris, France.,Service d'Hématologie Clinique, Hôpitaux Universitaires Saint Louis, Lariboisière, Fernand Widal, Université Paris Diderot, Paris, France
| | - Jeroen Lauf
- Department of Haematology, Internal Oncology and Stem Cell Transplantation, Ordensklinikum Linz Elisabethinen Hospital, Linz, Austria
| | - Anne-Sophie Alary
- Service d'Hématologie Biologique, Hôpitaux Universitaires Paris Centre, Université Paris Descartes, Paris, France
| | - Barbara Burroni
- Service d'Anatomopathologie, Hôpitaux Universitaires Paris Centre, Université Paris Descartes, Paris, France
| | - Olivier Kosmider
- Service d'Hématologie Biologique, Hôpitaux Universitaires Paris Centre, Université Paris Descartes, Paris, France
| | - Michaela Fontenay
- Service d'Hématologie Biologique, Hôpitaux Universitaires Paris Centre, Université Paris Descartes, Paris, France
| | - Marie C Béné
- Service d'Hématologie Biologique, CHU et Université de Nantes, Nantes, France
| | | | - Peter Bettelheim
- Department of Haematology, Internal Oncology and Stem Cell Transplantation, Ordensklinikum Linz Elisabethinen Hospital, Linz, Austria
| | - Valérie Bardet
- Service d'Hématologie-Immunologie-Transfusion, Hôpitaux Universitaires Paris Ile De France Ouest, Université Versailles Saint Quentin, Boulogne, France
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Pals ST, Kersten MJ, Spaargaren M. Targeting cell adhesion and homing as strategy to cure Waldenström's macroglobulinemia. Best Pract Res Clin Haematol 2016; 29:161-168. [PMID: 27825462 DOI: 10.1016/j.beha.2016.08.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 08/29/2016] [Accepted: 08/30/2016] [Indexed: 12/19/2022]
Abstract
Most B-cell malignancies strictly depend on signals from the microenvironment for their survival and proliferation. This niche-dependency can be regarded as their Achilles' heel and provides an excellent target for therapy. Waldenström's macroglobulinemia (WM) is characterized by the accumulation of neoplastic post-germinal center B cells within the bone marrow (BM). Interestingly, one third of the patients carry activating mutations in the chemokine receptor CXCR4, a key mediator of B cell and plasma cell homing to the BM. We have previously shown that signals from the B-cell antigen receptor (BCR) and from chemokine receptors play a central role in controlling the interaction of normal and malignant B cells with their microenvironment by regulating the activity of integrin adhesion molecules. Apart from controlling the homing and retention of lymphocytes within their growth- and survival niches, integrins also emit signals that directly promote cell growth and survival. By analogy to the successful treatment with BTK inhibitors, we propose that targeting pathways controlling integrin-mediated retention of the WM cells in the BM, thereby inducing 'homelessness' (anoikis) by mobilization of the malignant cells from their protective niches, may be an efficient treatment strategy for WM.
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Affiliation(s)
- Steven T Pals
- Department of Pathology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands; Lymphoma and Myeloma Center Amsterdam - LYMMCARE, The Netherlands.
| | - Marie José Kersten
- Department of Hematology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands; Lymphoma and Myeloma Center Amsterdam - LYMMCARE, The Netherlands
| | - Marcel Spaargaren
- Department of Pathology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands; Lymphoma and Myeloma Center Amsterdam - LYMMCARE, The Netherlands
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Porwit A, Fend F, Kremer M, Orazi A, Safali M, van der Walt J. Issues in diagnosis of small B cell lymphoid neoplasms involving the bone marrow and peripheral blood. Report on the Bone Marrow Workshop of the XVIIth meeting of the European Association for Haematopathology and the Society for Hematopathology. Histopathology 2016; 69:349-73. [PMID: 27208429 DOI: 10.1111/his.12999] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 05/12/2016] [Accepted: 05/19/2016] [Indexed: 01/01/2023]
Abstract
Small B cell lymphoid neoplasms are the most common lymphoproliferative disorders involving peripheral blood (PB) and bone marrow (BM). The Bone Marrow Workshop (BMW) organized by the European Bone Marrow Working Group (EBMWG) of the European Association for Haematopathology (EAHP) during the XVIIth EAHP Meeting in Istanbul, October 2014, was dedicated to discussion of cases illustrating how the recent advances in immunophenotyping, molecular techniques and cytogenetics provide better understanding and classification of these entities. Submitted cases were grouped into following categories: (i) cases illustrating diagnostic difficulties in chronic lymphocytic leukaemia (CLL); (ii) cases of BM manifestations of small B cell lymphoid neoplasms other than CLL; (iii) transformation of small B cell lymphoid neoplasms in the BM; and (iv) multiclonality and composite lymphomas in the BM. This report summarizes presented cases and conclusions of the BMW and provides practical recommendations for classification of the BM manifestations of small B cell lymphoid neoplasms based on the current state of knowledge.
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Affiliation(s)
- Anna Porwit
- Department of Clinical Sciences, Division of Oncology and Pathology, Faculty of Medicine, Lund University, Lund, Sweden.,Previous address: Department of Pathobiology and Laboratory Medicine, University Health Network, Toronto, ON, Canada
| | - Falko Fend
- Institute of Pathology and Neuropathology and Comprehensive Cancer Center, University Hospital Tübingen, Tübingen, Germany
| | - Marcus Kremer
- Institute of Pathology, Staedtisches Klinikum, München, Germany
| | - Attilio Orazi
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY, USA
| | | | - Jon van der Walt
- Department of Histopathology, Guy's and St Thomas' Hospitals, London, UK
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Sobhani M, Abdi J, Manujendra SN, Chen C, Chang H. PRIMA-1Met induces apoptosis in Waldenström's Macroglobulinemia cells independent of p53. Cancer Biol Ther 2016; 16:799-806. [PMID: 25803193 DOI: 10.1080/15384047.2015.1026482] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
PRIMA-1Met has shown promising preclinical activity in various cancer types. However, its effect on Waldenström's Macroglobulinemia (WM) cells as well as its exact mechanism of action is still elusive. In this study, we evaluated the anti- tumor activity of PRIMA-1Met alone and in combination with dexamethasone or bortezomib in WM cell lines and primary samples. Treatment of WM cells with PRIMA-1Met resulted in induction of apoptosis, inhibition of migration and suppression of colony formation. Upon PRIMA-1Met treatment, p73 was upregulated and Bcl-xL was down-regulated while no significant change in expression of p53 was observed. Furthermore, siRNA knockdown of p53 in WM cell line did not influence the PRIMA-1Met-induced apoptotic response whereas silencing of p73 inhibited latter response in WM cells. Importantly, combined treatment of BCWM-1 cells with PRIMA-1Met and dexamethasone or bortezomib induced synergistic reduction in cell survival. Our study provides insights into the mechanisms of anti-WM activity of PRIMA-1Met and supports further clinical evaluation of PRIMA-1Met as a potential novel therapeutic intervention in WM.
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Affiliation(s)
- Mona Sobhani
- a Division of Molecular and Cellular Biology; Toronto General Hospital Research Institute ; Toronto , Ontario , Canada
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Waldenström macroglobulinemia: clinical and immunological aspects, natural history, cell of origin, and emerging mouse models. ISRN HEMATOLOGY 2013; 2013:815325. [PMID: 24106612 PMCID: PMC3782845 DOI: 10.1155/2013/815325] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 07/26/2013] [Indexed: 12/22/2022]
Abstract
Waldenström macroglobulinemia (WM) is a rare and currently incurable neoplasm of IgM-expressing B-lymphocytes that is characterized by the occurrence of a monoclonal IgM (mIgM) paraprotein in blood serum and the infiltration of the hematopoietic bone marrow with malignant lymphoplasmacytic cells. The symptoms of patients with WM can be attributed to the extent and tissue sites of tumor cell infiltration and the magnitude and immunological specificity of the paraprotein. WM presents fascinating clues on neoplastic B-cell development, including the recent discovery of a specific gain-of-function mutation in the MYD88 adapter protein. This not only provides an intriguing link to new findings that natural effector IgM+IgD+ memory B-cells are dependent on MYD88 signaling, but also supports the hypothesis that WM derives from primitive, innate-like B-cells, such as marginal zone and B1 B-cells. Following a brief review of the clinical aspects and natural history of WM, this review discusses the thorny issue of WM's cell of origin in greater depth. Also included are emerging, genetically engineered mouse models of human WM that may enhance our understanding of the biologic and genetic underpinnings of the disease and facilitate the design and testing of new approaches to treat and prevent WM more effectively.
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