Enhanced DNA repair and genomic stability identify a novel HIV related Diffuse Large B-cell Lymphoma subtype [nanostring]
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ABSTRACT: Transcriptional and genomic profiling study of HIV positive and HIV negative Diffuse Large B-Cell Lymphoma (DLBCL). Tumors were subtyped using the Lymph2Cx assay. Only GCB (germinal center like B-cell) subtypes were then subjected to digitial gene expression profiling and array comparative genomic hybridization (aCGH). The study used total RNA extracted from FFPE DLBCL tumors derived from HIV(+) and HIV(-) patients to assess differential expression of known cancer genes. Gene expression was correlated with IHC and array CGH data.
Project description:Transcriptional and genomic profiling study of HIV positive and HIV negative Diffuse Large B-Cell Lymphoma (DLBCL). Tumors were subtyped using the Lymph2Cx assay. Only GCB (germinal center like B-cell) subtypes were then subjected to digitial gene expression profiling and array comparative genomic hybridization (aCGH). The study used DNA extracted from FFPE DLBCL tumors derived from HIV(+) and HIV(-) patients to assess copy number variation differences between the HIV(+) and HIV(-) cohorts. aCGH data was correlated with gene expression & IHC data.
Project description:We performed array comparative genomic hybridization (aCGH) and gene expression profiling in 203 samples of diffuse large B cell lymphoma (DLBCL). By gene expression, at least three molecular subtypes of DLBCL termed as germinal center B cell-like (GCB) DLBCL, activated B cell-like (ABC) DLBCL, and primary mediastinal B cell lymphoma (PMBL) can be distinguished. Combining gene expression profiling and aCGH, revealed copy number abnormalities that had strikingly different frequencies in the three molecular DLBCL subtypes. These data provide genetic evidence that the DLBCL subtypes are distinct diseases that utilize different oncogenic pathways. Keywords: clinical history design
Project description:The goal of this study is to identify the transcriptome differences between the two major subtypes of diffuse large B cell lymphoma (DLBCL). DLBCL is the most common form of non-Hodgkin’s lymphoma and has two major subtypes: germinal center B-cell-like (GCB) and activated B-cell-like (ABC). When compared to the GCB form, ABC lymphomas respond much more poorly to current therapies. To investigate how gene expression changes might contribute to this aggressive phenotype, we have used RNA-Seq to profile the whole transcriptome in 8 DLBCL cell lines (4 GCB subtype, 4 ABC) that are derived from patient tumors. 1,545 genes are differentially expressed between subtypes (FDR < 0.05), approximately 7% of the transcriptome. The vast majority of these genes (81%, n = 1251) are more highly expressed in the ABC cell lines. In contrast, only 294 genes (19%) are more highly expressed in the GCB cell lines. Half (n = 765) of the genes with greater ABC subtype expression demonstrate very low read counts (< 5) in the GCB cell types. Conversely, only 21 genes that are more highly expressed in GCB are unique to that subtype. The prevalence of such “on/off” genes indicates that the major differences between ABC and GCB DLBCL are due almost exclusively to additional gene expression in ABC, rather than the two subtypes having divergent but equally active genetic programs. Measurement and comparison of gene expression in 8 cell lines representing the 2 subtypes of DLBCL. 4 cell lines are subtyped as ABC and 4 are subtyped as GCB. 2 replicates are present for each cell line. (Cell line OCI-Ly19 was not included in the analysis because its gene expression clustered in between the subtypes, probably due to its EBV+ status. However, its sequencing runs have been included for completeness.)
Project description:The goal of this study is to identify the effect of the transcription factor STAT3 in the two major subtypes of diffuse large B cell lymphoma (DLBCL). STAT3 is a signal transducer that, when dysregulated, becomes a powerful oncogene found in many human cancers, including DLBCL. DLBCL is the most common form of non-Hodgkin’s lymphoma and has two major subtypes: germinal center B-cell-like (GCB) and activated B-cell-like (ABC). When compared to the GCB form, ABC lymphomas respond much more poorly to current therapies and often exhibit overexpression or overactivation of STAT3. To investigate how STAT3 might contribute to this aggressive phenotype, we have used ChIP-Seq to identify STAT3 binding sites in 8 DLBCL cell lines (4 GCB subtype, 4 ABC) that are derived from patient tumors. 10,337 distinct STAT3 binding regions are occupied in at least two of the eight cell lines. One third (n = 3524) are differentially bound by STAT3 between the two subtypes (FDR < 0.05). More BRs are strongly bound in ABC than in GCB: 44% of differentially bound BRs (n = 1550) show more STAT3 binding in GCB, while 56% (n = 1974) are more strongly bound in ABC. Identification and comparison of STAT3 transcription factor binding sites in 8 cell lines that represent the 2 subtypes of DLBCL. 4 cell lines are subtyped as ABC and 4 are subtyped as GCB. 2-9 replicates and 1 input control are present for each cell line. (Cell line OCI-Ly19 was not included in the final analysis because RNA-Seq showed that its gene expression clustered in between the subtypes, probably due to its EBV+ status. However, its peak calls were used in intermediate steps of the analysis pipeline. Its sequencing runs have been included for completeness.)
Project description:We performed array comparative genomic hybridization (aCGH) and gene expression profiling in 203 samples of diffuse large B cell lymphoma (DLBCL). By gene expression, at least three molecular subtypes of DLBCL termed as germinal center B cell-like (GCB) DLBCL, activated B cell-like (ABC) DLBCL, and primary mediastinal B cell lymphoma (PMBL) can be distinguished. Combining gene expression profiling and aCGH, revealed copy number abnormalities that had strikingly different frequencies in the three molecular DLBCL subtypes. These data provide genetic evidence that the DLBCL subtypes are distinct diseases that utilize different oncogenic pathways. Keywords: clinical history design The retrospective study included RNA and DNA extracted from 203 clinical samples.
Project description:Objection: To evaluate a qPCR-based 32-gene expression assay to determine the cell-of-origin (COO) of diffuse large B-cell lymphoma (DLBCL) with formalin-fixed paraffin-embedded (FFPE) tissue. Methods: The most established subtyping algorithm, the COO model, categorizes DLBCL into activated B-cell (ABC) and germinal center B-cell (GCB)-like subgroups through gene expression profiling. Biopsy of DLBCL patients with paired FFPE and fresh frozen tissue were collected to assign COO based on the immunohistochemistry (IHC) algorithm (Han’s algorithm), qPCR-based 32-gene expression assay (DLBCL-COO assay) and global gene expression profiling with RNA-seq. Results: The DLBCL-COO assay demonstrated a significantly superior concordance of COO determination with the “gold standard” RNA-seq, comparing with the IHC assignment with Han’s algorithm (91.9% versus 77.5%; P = 0.005). Furthermore, overall survival of GCB patients defined by DLBCL-COO assay was superior significantly towards the ABC patients (Figure 2B, P = 0.023). This effect was not seen when tumors were classified by IHC algorithm. Conclusions: The DLBCL-COO assay provides flexibility and accuracy in DLBCL subtype characterization. These subtype distinctions should help guiding prognostic and therapeutic options for the patients in our daily practice.
Project description:Primary bone diffuse large B-cell lymphoma (PB-DLBCL) is a rare extranodal lymphoma subtype. This retrospective study elucidates the currently unknown genetic background of a large clinically well-annotated cohort of DLBCL with osseous localizations (O-DLBCL), including PB-DLBCL. 103 O-DLBCL patients were included and compared with 63 (extra)nodal non-osseous (NO)-DLBCLs with germinal center B-cell phenotype (NO-DLBCL-GCB). Cell-of-origin (COO) was determined by immunohistochemistry and gene-expression-profiling (GEP) using (extended)-NanoString/Lymph2Cx. Mutational profiles were identified with targeted next-generation deep-sequencing, including 52 B-cell lymphoma-relevant genes. O-DLBCLs, including 34 PB-DLBCL, were predominantly classified as GCB-phenotype based on immunohistochemistry (74%) and NanoString analysis (88%). Unsupervised hierarchical clustering of an extended-NanoString/Lymph2Cx demonstrated significantly different GEP-clusters for PB-DLBCL as opposed to NO-DLBCL-GCB (P<0.001). Expression levels of 23 genes of two different targeted GEP-panels, indicated a centrocyte–like phenotype for PB-DLBCL, whereas NO-DLBCL-GCB showed a centroblast-like constitution. PB-DLBCL had significantly more frequent mutations in four GCB-associated genes, i.e. B2M, EZH2, IRF8, and TNFRSF14, compared to NO-DLBCL-GCB (P=0.031, P=0.010, P=0.047, and P=0.003). PB-DLBCL with its corresponding specific mutational profile were significantly associated with a superior overall survival compared to equivalent Ann Arbor limited-stage I/II NO-DLBCL-GCB (P=0.011). This study is the first to demonstrate that PB-DLBCL is characterized by a GCB-phenotype, with a centrocyte-like GEP-pattern and a GCB-associated mutational profile (both involved in immune surveillance) and a favorable prognosis. These novel biology-associated features provide evidence that PB-DLBCL represents a distinct extranodal DLBCL entity and its specific mutational landscape holds potential for targeted therapies (e.g. EZH2-inhibitors). The NanoString analsyis consisted out of 219 probes for Lymph2Cx classifier (COO), MYC-activity GEP score, CNV-associated GEP signature, consensus clustering, and immune-ratio signature. This custome probeset was used to differentiate GEPs between osseous and non-osseos DLBCL of the GCB-phenotype.
Project description:Gene expression profiling (GEP) of ARL patient samples was done to determine whether gene expression signatures derived from HIV- lymphomas retained their ability to molecularly classify HIV+ lymphomas. The GEP-based predictors robustly classified ARL tumors, distinguishing molecular Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL), as well as activated B-cell-like (ABC) and germinal center B-cell-like (GCB) molecular subtypes of DLBCL. Gene expression profiles were used to identify coordinately regulated gene sets and pathways that differ between HIV+ and HIV- lymphomas of corresponding molecular subtype. Frozen tumor biopsies were obtained from 20 HIV-positive patients with an AIDS-defining lymphoma. Cases were ascertained at the University of Nebraska Medical Center and through the NCI AIDS and Cancer Specimen Resource tumor bank. Sufficient RNA for hybridization to Affymetrix U133 plus 2 arrays was obtained on 17 ARL cases. Details of all 20 HIV-positive patients can be found in the supplementary file below. Third party array data from HIV- lymphomas of corresponding molecular subtype were used for the comparison and molecular classification of the HIV+ cases in this study. The third party HIV- lymphoma samples include the following. [1] HIV- lymphoma, BL cases: 84 samples profiled on the Affymetrix HG U133 Plus 2 array. The data are publicly available on the website companion to Dave et al. NEJM 2006; Volume 354:13-24 (http://llmpp.nih.gov/BL/) and were used 'as is' (ie, not reanalyzed). [2] HIV- lymphoma, DLBCL cases: 200 of the 414 cases in Series GSE10846 (listed in the supplementary file below). These included all R-CHOP treated cases of either ABC or GCB subtype. These data were also used as is. These data were published in Lenz et al. NEJM 2008; Volume 359: 2313-2323.
Project description:Gene expression profiling (GEP) of ARL patient samples was done to determine whether gene expression signatures derived from HIV- lymphomas retained their ability to molecularly classify HIV+ lymphomas. The GEP-based predictors robustly classified ARL tumors, distinguishing molecular Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL), as well as activated B-cell-like (ABC) and germinal center B-cell-like (GCB) molecular subtypes of DLBCL. Gene expression profiles were used to identify coordinately regulated gene sets and pathways that differ between HIV+ and HIV- lymphomas of corresponding molecular subtype.
Project description:Gene expression profiling (GEP) of ARL patient samples was done to determine whether gene expression signatures derived from HIV- lymphomas retained their ability to molecularly classify HIV+ lymphomas. The GEP-based predictors robustly classified ARL tumors, distinguishing molecular Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL), as well as activated B-cell-like (ABC) and germinal center B-cell-like (GCB) molecular subtypes of DLBCL. Gene expression profiles were used to identify coordinately regulated gene sets and pathways that differ between HIV+ and HIV- lymphomas of corresponding molecular subtype.