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:Using high-resolution genomic microarray analysis, a distinct genomic profile was defined in 114 samples from patients with splenic marginal zone lymphoma (SMZL). Notably, deletion or uniparental disomy of chromosome 7q were detected in 39% of SMZLs but in only 9 of 170 (5%) mature B-cell lymphomas (p<10-6). The presence of unmutated IgVH genes, genomic complexity, 17p13-P53 deletion and 8q gain including MYC gene, but not 7q deletion, were correlated with shorter overall survival. Extensive mapping analyses narrowed down the commonly deleted region to 2.7 Mb. in 7q32.1-q32.2 from SND1 to COPG2 genes. High-throughput sequencing analysis of the 7q32 deleted segment in SMZL cells did not identify bi-allelic deletions, insertions or clear pathogenic mutations, but detected six single nucleotide changes in IRF5 (n=2), TMEM209 (n=2), CALU (n=1) and ZC3HC1 (n=1). Comparative expression analysis found that IRF5, TMEM209 and CALU genes had down-regulated expression in lymphomas with 7q32 deletion vs. non-deleted tumors. Ectopic expression of IRF5 in marginal-zone lymphoma cells decreased cell proliferation and induced apoptosis. These results indicate that small deletions, insertions and/or point mutations inactivating genes within 7q32 are not common events in SMZL. Further studies are required to evaluate the putative role of IRF5 in SMZL pathogenesis. 9 samples. 6 patient samples with 7q32 deletion and 3 patient samples without 7q32 deletion. Splenic Marginal Zone Lymphoma patient samples with 7q32 deletion vs. Splenic Marginal Zone Lymphoma patient samples without 7q32 deletion
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:We studied marginal zone B-cell lymphomas of the gastrointestinal tract including seven small cell MALT lymphomas, eight composite lymphomas and thirteen large cell variants using SNP-array profiling. We found an increase of genomic complexity with lymphoma progression, and could identify gains of prominent (proto)oncogenes REL, ETS1, PTPN1, PTEN and KRAS that were associated exclusively with the large cell presentation of MALT lymphoma. Losses of ADAM3A and SCAPER, as well as gains of SIRPB1 occur during progression from small cell to large cell lymphoma. In two case studies, we examined lymphoma progression comparing two different regions of the same tumor and material acquired at two different time points from another lymphoma. Our analyses reveal genomic heterogeneity in both cases, supporting the theory of an oligoclonal tumor evolution model for MALT lymphomas and its variants.
Project description:Using high-resolution genomic microarray analysis, a distinct genomic profile was defined in 114 samples from patients with splenic marginal zone lymphoma (SMZL). Notably, deletion or uniparental disomy of chromosome 7q were detected in 39% of SMZLs but in only 9 of 170 (5%) mature B-cell lymphomas (p<10-6). The presence of unmutated IgVH genes, genomic complexity, 17p13-P53 deletion and 8q gain including MYC gene, but not 7q deletion, were correlated with shorter overall survival. Extensive mapping analyses narrowed down the commonly deleted region to 2.7 Mb. in 7q32.1-q32.2 from SND1 to COPG2 genes. High-throughput sequencing analysis of the 7q32 deleted segment in SMZL cells did not identify bi-allelic deletions, insertions or clear pathogenic mutations, but detected six single nucleotide changes in IRF5 (n=2), TMEM209 (n=2), CALU (n=1) and ZC3HC1 (n=1). Comparative expression analysis found that IRF5, TMEM209 and CALU genes had down-regulated expression in lymphomas with 7q32 deletion vs. non-deleted tumors. Ectopic expression of IRF5 in marginal-zone lymphoma cells decreased cell proliferation and induced apoptosis. These results indicate that small deletions, insertions and/or point mutations inactivating genes within 7q32 are not common events in SMZL. Further studies are required to evaluate the putative role of IRF5 in SMZL pathogenesis. Affymetrix GeneChip 50k-XbaI and/or 250-NspI/StyI SNP microarrays were performed for 59 SMZL samples and 4 Marginal Zone cell lines according to the manufacturer's directions.
Project description:We studied marginal zone B-cell lymphomas of the gastrointestinal tract including seven small cell MALT lymphomas, eight composite lymphomas and thirteen large cell variants using SNP-array profiling. We found an increase of genomic complexity with lymphoma progression, and could identify gains of prominent (proto)oncogenes REL, ETS1, PTPN1, PTEN and KRAS that were associated exclusively with the large cell presentation of MALT lymphoma. Losses of ADAM3A and SCAPER, as well as gains of SIRPB1 occur during progression from small cell to large cell lymphoma. In two case studies, we examined lymphoma progression comparing two different regions of the same tumor and material acquired at two different time points from another lymphoma. Our analyses reveal genomic heterogeneity in both cases, supporting the theory of an oligoclonal tumor evolution model for MALT lymphomas and its variants. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from cryopreserved tumor samples. Copy number and loss of heterozygosity analysis of Affymetrix GenomeWide SNP 6.0 arrays was performed for 7 small cell MALT lymphomas, 8 large cell areas of Composite lymphomas and 13 large cell variants. Two independant hybridizations of one of the small cell MALT lymphoma and one of the large cell areas of Composite lymphoma Samples were performed.
Project description:Splenic marginal zone lymphoma (SMZL) is an indolent B-cell lymphoproliferative disorder characterised by 7q32 deletion, but the target genes of this deletion remain unknown. In order to elucidate the genetic target of this deletion, we performed an integrative analysis of the genetic, epigenetic, transcriptomic and miRNomic data. High resolution array comparative genomic hybridization of 56 cases of SMZL delineated a minimally deleted region (2.8Mb) at 7q32, but showed no evidence of any cryptic homozygous deletion or recurrent breakpoint in this region. Integrative transcriptomic analysis confirmed significant under-expression of a number of genes in this region in cases of SMZL with deletion, several of which showed hypermethylation. In addition, a cluster of 8 miRNA in this region showed under-expression in cases with the deletion, and three (miR-182/96/183) were also significantly under-expressed (P <0.05) in SMZL relative to other lymphomas. Genomic sequencing of these miRNA and IRF5, a strong candidate gene, did not show any evidence of somatic mutation in SMZL. Keywords: Genome variation profiling by genome tiling array For aCGH. 21 fresh frozen splenic samples from patients with SMZL were hybridized against a reference control of pooled PBMC genomic DNA from 10 normal subjects. High-resolution oligonucleotide analysis of copy number variations in splenic marginal zone lymphoma (SMZL) in regions of recurrent alteration. Regions included on the array: 7q (2k resolution) and regions of interest on chromosomes 3q, 6q and 9q at 12k resolution.
Project description:Using high-resolution genomic microarray analysis, a distinct genomic profile was defined in 114 samples from patients with splenic marginal zone lymphoma (SMZL). Notably, deletion or uniparental disomy of chromosome 7q were detected in 39% of SMZLs but in only 9 of 170 (5%) mature B-cell lymphomas (p<10-6). The presence of unmutated IgVH genes, genomic complexity, 17p13-P53 deletion and 8q gain including MYC gene, but not 7q deletion, were correlated with shorter overall survival. Extensive mapping analyses narrowed down the commonly deleted region to 2.7 Mb. in 7q32.1-q32.2 from SND1 to COPG2 genes. High-throughput sequencing analysis of the 7q32 deleted segment in SMZL cells did not identify bi-allelic deletions, insertions or clear pathogenic mutations, but detected six single nucleotide changes in IRF5 (n=2), TMEM209 (n=2), CALU (n=1) and ZC3HC1 (n=1). Comparative expression analysis found that IRF5, TMEM209 and CALU genes had down-regulated expression in lymphomas with 7q32 deletion vs. non-deleted tumors. Ectopic expression of IRF5 in marginal-zone lymphoma cells decreased cell proliferation and induced apoptosis. These results indicate that small deletions, insertions and/or point mutations inactivating genes within 7q32 are not common events in SMZL. Further studies are required to evaluate the putative role of IRF5 in SMZL pathogenesis. CGH analysis was performed for 76 Splenic Marginal Zone lymphoma patient samples. Production and validation of the array, hybridization methods and analytical procedures have been described elsewhere: Snijder AM, Nowak N, Segraves R, et al. Assembly of microarrays for genome-wide measurement of DNA copy number. Nat Genet. 2001;29:263-264.