Project description:Follicular lymphoma (FL) is one of the most common types of indolent B-cell lymphoma in Western countries. FL commonly transforms to more aggressive diffuse large B-cell lymphoma (DLBCL) at reported frequencies between 15 - 60%. We have used microarray comparative genomic hybridisation (aCGH) at 1 Mb resolution to study copy number changes in paired tumor samples (primary FL and a subsequent tDLBCL) as well as de novo DLBCL cases to outline genetic mechanisms of transformation from follicular lymphoma to diffuse large B-cell lymphoma.
Project description:Follicular lymphoma (FL) is one of the most common types of indolent B-cell lymphoma in Western countries. FL commonly transforms to more aggressive diffuse large B-cell lymphoma (DLBCL) at reported frequencies between 15 - 60%. We have used microarray comparative genomic hybridisation (aCGH) at 1 Mb resolution to study copy number changes in paired tumor samples (primary FL and a subsequent tDLBCL) as well as de novo DLBCL cases to outline genetic mechanisms of transformation from follicular lymphoma to diffuse large B-cell lymphoma. Single hybridization per case. 21 FL, 31 transformed DLBCL, 29 de novo DLBCL (10 GC and 19 non-GC DLBCL). Tumor labelled with Cy5 and reference with Cy3. Mixture of 20 normal male or female genomic DNA was used in sex-mismatched hybridization.
Project description:This SuperSeries is composed of the following subset Series: GSE30357: Chip-chip from human diffuse large B cell lymphoma cell lines with IRF8 GSE30358: Mouse B cell lymphoma cell lines:IRF8 knockdown cells vs. Control GSE30519: Chip-chip from mouse diffuse large B cell lymphoma cell lines with IRF8 GSE30520: Chip-chip from mouse diffuse large B cell lymphoma cell lines with PU.1 Refer to individual Series
Project description:The pathogenesis of diffuse large B cell lymphomas (DLBCL) is only partly understood. We analyzed 148 DLBCL by high resolution single nucleotide polymorphism (SNP)-chips to characterize genomic imbalances. Seventy-nine cases were of the germinal center B-cell like (GCB) type of DLBCL, 49 of the activated B-cell like (ABC) subtype and 20 were type 3 DLBCL. Twenty-four regions of recurrent genomic gains and 38 regions of recurrent genomic losses were identified over the whole cohort, with a median of 25 imbalances per case for ABC-DLBCL and 19 per case for GCB-DLBCL. Several recurrent copy number changes showed differential frequencies in the GCB- and ABC-DLBCL subgroups, including gains of HDAC7A predominantly in GCB-DLBCL (38% of cases) and losses of BACH2 and CASP8AP2 predominantly in ABC-DLBCL (35%), hinting at disparate pathogenetic mechanisms in these entities. Correlating gene expression and copy number revealed a strong gene dosage effect in all tumors, with 34% of probesets showing a concordant expression change in affected regions. Two new potential tumor suppressor genes emerging from the analysis, CASP3 and IL5RA, were sequenced in 10 and 16 candidate cases, respectively. However, no mutations were found, pointing to a potential haploinsufficiency effect of these genes, considering their reduced expression in cases with deletions. This work thus describes differences and similarities in the landscape of genomic aberrations in the DLBCL subgroups in a large collection of cases, confirming already known targets, but also discovering novel copy number changes with possible pathogenetic relevance. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from cryopreserved lymph node biopsies of tumor samples.
Project description:Mantle cell lymphoma (MCL) is a lymphoma characterized by aberrant activation of CCND1/cyclin D1 followed by sequential genetic abnormalities. Genomic abnormalities in MCL have been extensively examined by classical cytogenetics and microarray-based comparative genomic hybridization techniques, pointing out a number of alterations in genomic regions that correlate with the neoplastic phenotype and survival. Recently, single nucleotide polymorphism genomic microarrays (SNP-chip) have been developed and used for analysis of cancer genomics. This technique allows detection of genomic changes with higher resolution, including loss of heterozygosity without changes of gene dosage, so-called acquired uniparental disomy (aUPD). As a result of the analysis, known alterations were confirmed by SNP arrays, including deletion of INK4A/ARF, duplication/amplification of MYC, deletion of ATM, and deletion of TP53. We also identified a duplication/amplification that occurred at 13q involving oncogenic microRNA, miR17-92. We found other genomic abnormalities, including duplication/amplification of cyclin D1, del(1p), del(6q), dup(3q) and dup(18q). Our SNP-chip analysis detected these abnormalities at high resolution, allowing us to narrow the size of the commonly deleted regions, including 1p and 6q. Our SNP-chip analysis detected a number of aUPD sites, including whole chromosome 9 aUPD and 9p aUPD. We also found an MCL case with 19p, leading to homozygous deletion of TNFSF genes. keyword: SNP-chip; Kawmata_MCL
Project description:Pet dogs may provide a useful large-animal model of spontaneously occuring non-Hodgkin lymphoma, but complete molecular characterization is lacking. We used gene expression microarrays to molecularly characterize canine lymphoma, and found similarities between canine B-cell lymphoma and human diffuse large B-cell lymphoma.
Project description:For sporadic Burkitt lymphoma (BL) few genetic lesions are known besides the pathognomonic IG-MYC translocations. Thirtynine molecularly-defined BL were analyzed with high-resolution single-nucleotide polymorphism chips for genomic imbalances and uniparental disomy (UPD). Imbalances were correlated to transcript profiling and selected miRNA analysis. Translocations affecting the MYC locus were studied by fluoresence in situ hybridization. We detected 528 copy number changes, defining 29 recurrently imbalanced regions. 518 regions of UPD were found, but these were rarely recurrent. Combined imbalance mapping and transcript profiling revealed a profound correlation between copy number and expression. Several recurrent imbalances affected the MYC pathway: The miRNA-supercluster 17-92 was frequently gained and the transcription factor E2F2 was recurrently deleted. Molecular BL lacking MYC translocations showed MYC gains. Amplifications of the polymerase iota gene were associated with increased genomic instability. The present findings suggests that UPDs play no major role in the pathogenesis of BL, whereas some genes may contribute to BL development through gene dosage effects. Amplifications of the polymerase iota gene may be functionally linked with increased genomic instability in BL. The pattern and rarity of chromosomal changes detectable even at the high resolution employed here, together with aberrations of genes regulating MYC activity, support that deregulation of the MYC pathway is the major force driving BL pathogenesis, but show that this deregulation is more complex than previously known. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from whole tissue. Copy number and LOH analysis of 500K SNP arrays was performed for 30 molecularly-defined Burkitt lymphomas. Genotyping was performed using the BRLMM-algorithm. Only a single 250k Chip was performed for nine additional Burkitts. 20 normal references (10 of those hybridized to nsp-chips) extracted from healthy blood donors, used as normals in the analysis in addition to the HapMap references provided by Affymetrix, are included in the set.
Project description:The pathogenesis of diffuse large B cell lymphomas (DLBCL) is only partly understood. We analyzed 148 DLBCL by high resolution single nucleotide polymorphism (SNP)-chips to characterize genomic imbalances. Seventy-nine cases were of the germinal center B-cell like (GCB) type of DLBCL, 49 of the activated B-cell like (ABC) subtype and 20 were type 3 DLBCL. Twenty-four regions of recurrent genomic gains and 38 regions of recurrent genomic losses were identified over the whole cohort, with a median of 25 imbalances per case for ABC-DLBCL and 19 per case for GCB-DLBCL. Several recurrent copy number changes showed differential frequencies in the GCB- and ABC-DLBCL subgroups, including gains of HDAC7A predominantly in GCB-DLBCL (38% of cases) and losses of BACH2 and CASP8AP2 predominantly in ABC-DLBCL (35%), hinting at disparate pathogenetic mechanisms in these entities. Correlating gene expression and copy number revealed a strong gene dosage effect in all tumors, with 34% of probesets showing a concordant expression change in affected regions. Two new potential tumor suppressor genes emerging from the analysis, CASP3 and IL5RA, were sequenced in 10 and 16 candidate cases, respectively. However, no mutations were found, pointing to a potential haploinsufficiency effect of these genes, considering their reduced expression in cases with deletions. This work thus describes differences and similarities in the landscape of genomic aberrations in the DLBCL subgroups in a large collection of cases, confirming already known targets, but also discovering novel copy number changes with possible pathogenetic relevance. Affymetrix HGU133A arrays were performed according to the manufacturer's directions on RNA extracted from cryopreserved lymph node biopsies of tumor samples.
Project description:Pet dogs may provide a useful large-animal model of spontaneously occuring non-Hodgkin lymphoma, but complete molecular characterization is lacking. We used gene expression microarrays to molecularly characterize canine lymphoma, and found similarities between canine B-cell lymphoma and human diffuse large B-cell lymphoma. We isolated RNA from pre-treatment biopsies from dogs with B-cell lymphoma and performed gene expression profiling.
Project description:T-cell prolymphocytic leukemina (T-PLL) is an agressive lymphoma derived from mature T-cells, which is in most cases characterized by the presence of an inv(14)(q11q32) and a characteristic pattern of secondary chromosomal abberations. We used microarrays to compare the transcriptomes of eight immunomagnetically purified CD3+ normal donor derived peripheral blood cells with five highly purified inv(14)-positive T-PLL blood samples. Experiment Overall Design: Purified T-PLL cells and normal T-cells were analyzed on microarrays to identify differentially expressed genes. High-resolution copy number determination using SNP-chip technology and FISH in twelve inv(14)-positive T-PLL showed that differentially expressed genes clustered significantly in regions affectd by recurrent chromosomal imbalances.