Project description:Lymphoplasmacytic lymphomas and marginal zone lymphomas of nodal, extra-nodal and splenic types account for 10% of non-Hodgkin lymphomas. They are similar at the cell differentiation level, sometimes making difficult to distinguish them from other indolent non-Hodgkin lymphomas. To better characterize their genetic basis, we performed array-based comparative genomic hybridization in 101 marginal zone lymphomas (46 MALT, 35 splenic and 20 nodal marginal zone lymphomas) and 13 lymphoplasmacytic lymphomas. Overall, 90.1% exhibited copy-number abnormalities. Lymphoplasmacytic lymphomas demonstrated the most complex karyotype (median=7 copy-number abnormalities), followed by MALT (4), nodal (3.5) and splenic marginal zone lymphomas (3). A comparative analysis exposed a group of copy-number abnormalities shared by several or all the entities with few disease-specific abnormalities. Gain of chromosomes 3, 12 and 18 and loss of 6q23-q24 (TNFAIP3) were identified in all entities. Losses of 13q14.3 (MIRN15A-MIRN16-1) and 17p13.3-p12 (TP53) were found in lymphoplasmacytic and splenic marginal zone lymphomas; loss of 11q21-q22 (ATM) in nodal, splenic marginal zone and lymphoplasmacytic lymphomas; loss of 7q32.1-q33 in MALT, splenic and lymphoplasmacytic lymphomas. Abnormalities affecting the NF-kB pathway were observed in 70% of MALT and lymphoplasmacytic lymphomas and 30% of splenic and nodal marginal zone lymphomas, suggesting distinct roles of this pathway in the pathogenesis/progression of these subtypes. Elucidation of the genetic alterations contributing to the pathogenesis of these lymphomas may guide to design specific therapeutic approaches.
Project description:Lymphoplasmacytic lymphomas and marginal zone lymphomas of nodal, extra-nodal and splenic types account for 10% of non-Hodgkin lymphomas. They are similar at the cell differentiation level, sometimes making difficult to distinguish them from other indolent non-Hodgkin lymphomas. To better characterize their genetic basis, we performed array-based comparative genomic hybridization in 101 marginal zone lymphomas (46 MALT, 35 splenic and 20 nodal marginal zone lymphomas) and 13 lymphoplasmacytic lymphomas. Overall, 90.1% exhibited copy-number abnormalities. Lymphoplasmacytic lymphomas demonstrated the most complex karyotype (median=7 copy-number abnormalities), followed by MALT (4), nodal (3.5) and splenic marginal zone lymphomas (3). A comparative analysis exposed a group of copy-number abnormalities shared by several or all the entities with few disease-specific abnormalities. Gain of chromosomes 3, 12 and 18 and loss of 6q23-q24 (TNFAIP3) were identified in all entities. Losses of 13q14.3 (MIRN15A-MIRN16-1) and 17p13.3-p12 (TP53) were found in lymphoplasmacytic and splenic marginal zone lymphomas; loss of 11q21-q22 (ATM) in nodal, splenic marginal zone and lymphoplasmacytic lymphomas; loss of 7q32.1-q33 in MALT, splenic and lymphoplasmacytic lymphomas. Abnormalities affecting the NF-kB pathway were observed in 70% of MALT and lymphoplasmacytic lymphomas and 30% of splenic and nodal marginal zone lymphomas, suggesting distinct roles of this pathway in the pathogenesis/progression of these subtypes. Elucidation of the genetic alterations contributing to the pathogenesis of these lymphomas may guide to design specific therapeutic approaches. One hundred fourteen patients were included in this study: 46 MALT lymphomas (22 pulmonary, 11 salivary glands, 7 lacrimal glands and 6 gastrointestinal), 35 splenic marginal zone lymphomas, 20 nodal marginal zone lymphomas and 13 non-Waldenström’s Macroglobulinemia lymphoplasmacytic lymphomas. All cases were reviewed prior to study on paraffin sections with immunohistochemistry. Sections of each frozen tissue used for study were also reviewed by histological examination and immunohistochemistry before was submitted for the study.
Project description:Molecular cloning of a t(10;14)(q24;q32) from a B-cell lymphoma showed a recurrent breakpoint in homeobox NKX2-3 gene, which was highly expressed in comparison to non-expressing mature B lymphocytes. Epigenetically-mediated NKX2-3 over-expression was selectively found in patients with splenic marginal-zone lymphoma, MALT lymphoma and extranodal diffuse large-cell lymphoma. In young mice, restricted expression of NKX2-3 to lymphocytes activated multiple integrins (LFA-1, VLA-4, MAC-1), adhesion molecules (ICAM-1, MadCAM-1, L-selectin) and the chemokine receptor CXCR4 that enhanced their homing and migration to splenic tissues, whereby they were retained, progressively accumulating to form non-clonal tumors. At 18 months, B cells acquired genomic rearrangements and generated clonal B-cell lymphomas mirroring the spectrum of human NKX2-3-expressing tumors. Mouse and human lymphomas displaying NKX2-3 expression shared histopahological, genomic and molecular features, including canonical NF-KB activation. NF-KB inhibition reduced tumorigenecity of NKX2-3-positive lymphomas. Our study reveals that oncogenic NKX2-3 promotes B-cell lymphomagenesis by disturbing lymphocyte dynamics. Comparisson of global gene expression profiling between Emu-NKX2-3 transgenes mice and wild type mice.
Project description:Molecular cloning of a t(10;14)(q24;q32) from a B-cell lymphoma showed a recurrent breakpoint in homeobox NKX2-3 gene, which was highly expressed in comparison to non-expressing mature B lymphocytes. Epigenetically-mediated NKX2-3 over-expression was selectively found in patients with splenic marginal-zone lymphoma, MALT lymphoma and extranodal diffuse large-cell lymphoma. In young mice, restricted expression of NKX2-3 to lymphocytes activated multiple integrins (LFA-1, VLA-4, MAC-1), adhesion molecules (ICAM-1, MadCAM-1, L-selectin) and the chemokine receptor CXCR4 that enhanced their homing and migration to splenic tissues, whereby they were retained, progressively accumulating to form non-clonal tumors. At 18 months, B cells acquired genomic rearrangements and generated clonal B-cell lymphomas mirroring the spectrum of human NKX2-3-expressing tumors. Mouse and human lymphomas displaying NKX2-3 expression shared histopahological, genomic and molecular features, including canonical NF-KB activation. NF-KB inhibition reduced tumorigenecity of NKX2-3-positive lymphomas. Our study reveals that oncogenic NKX2-3 promotes B-cell lymphomagenesis by disturbing lymphocyte dynamics.
Project description:Ataxia-telangiectasia mutated (ATM) kinase plays a central role in maintaining genomic integrity. In both humans and mice, ATM deficiency is associated with an increased incidence of lymphoid cancers that are primarily T cell in origin. We demonstrate here that when T cells are removed as targets for lymphomagenesis and as mediators of immune surveillance, ATM-deficient mice exclusively develop early onset IgM+ B cell lymphomas that by histology and gene expression profiling resemble the activated B cell-like (ABC) subset of human diffuse large B cell lymphomas (DLBCL). These ATM-deficient B cell tumors show considerable chromosomal instability and a recurrent genomic amplification of a 4.48 Mb region on chromosome 18 that contains Malt1 and is orthologous to a region similarly amplified in human ABC-DLBCL. Further, the amplification of Malt1 in these lymphomas correlates with their dependence on NF-kB, MALT1, and BCR signaling for survival, paralleling human ABC-DLBCL. This study reveals that ATM protects against development of B cell lymphomas that model human ABC-DLBCL and identifies a role for T cells in preventing the emergence of these tumors.
Project description:Ocular adnexal lymphoma is a rare subtype of non-Hodgkin lymphoma. DIA LC-MS of serum samples collected at diagnosis was performed on 38 ocular adnexal lymphomas (28 extranodal marginal zone lymphomas, and 10 diffuse large B-cell lymphomas), and 20 controls (10 idiopathic orbital inflammation, and 10 reactive lymphoid hyperplasia). Complete clinicopathologic features of these patients were collected.