Project description:Intrinsic resistance of lymphoma cells to apoptosis is a probable mechanism causing chemotherapy resistance and eventual fatal outcome in patients with diffuse large B cell lymphomas (DLBCL). We investigated whether microarray expression profiling of apoptosis related genes predicts clinical outcome in 46 patients with primary nodal DLBCL. Unsupervised cluster analysis using genes involved in apoptosis (N=246) resulted in 3 separate DLBCL groups partly overlapping with GCB versus ABC like phenotype. One group with poor clinical outcome was characterized by high expression levels of pro-and anti-apoptotic genes involved in the intrinsic apoptosis pathway. A 2nd group, also with poor clinical outcome, was characterized by high levels of apoptosis inducing cytotoxic effector genes, possibly reflecting a cellular cytotoxic immune response. The 3rd group showing a favourable outcome was characterized by low expression levels of genes characteristic for both other groups. Our results suggest that chemotherapy refractory DLBCL are characterized either by an intense cellular cytotoxic immune response or by constitutive activation of the intrinsic mediated apoptosis pathway with concomitant downstream inhibition of this apoptosis pathway. Consequently, strategies neutralizing the function of apoptosis-inhibiting proteins might be effective as alternative treatment modality in part of chemotherapy refractory DLBCL. Keywords: expression profiling B lymphomas
Project description:Diffuse large B-cell lymphoma (DLBCL) is currently divided into three main molecular subtypes, defined by gene expression profiling (GEP): Germinal Center B-cell like (GCB), Activated B-Cell like (ABC), and Primary Mediastinal B-cell Lymphoma (PMBL). DLBCL subtypes were determined according to patients' gene expression profiles.
Project description:Nijmegen-breakage syndrome (NBS, OMIM #251260) is an autosomal recessive chromosomal instability syndrome characterized by a very distinct phenotype (microcephaly, growth retardation, immunodeficiency) associated with increased predisposition to develop malignancies, particularly of lymphoid origin (by the age of 20 years, over 40% of NBS patients develop cancer). Immunological lineage of lymphomas in NBS significantly differs from Non-Hodgkin Lymphomas (NHL) entities observed in general pediatric population as well as in primary immunodeficiencies. There is a strong predominance of diffuse large B-cell lymphoma (DLBCL) and T cell lymphoblastic lymphoma (T-LBL/ALL), all showing clonal Ig/TCR rearrangements. In the current study we aimed to examined gene expression signature of metabolic pathways in DLBCL cells.
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:Primary diffuse large B cell lymphomas of different immune-privileged sites (IP-DLBCL) share many clinical and biological features, such as a relatively poor prognosis, preferential dissemination to other immune-privileged sites and deletion of the HLA region, which suggests that IP-DLBCL represents a separate entity. To further investigate the nature of IP-DLBCL, we investigated site-specific genomic aberrations in 16 testicular, 9 central nervous system (CNS) and 15 nodal DLBCL using array-CGH. We also determined minimal common regions of gain and loss. Using robust algorithms, the array-CGH data were combined with gene expression data to explore pathways deregulated by chromosomal aberrations. Keywords: comparative genomic hybridisation, gene expression, tumor type comparison
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:Primary diffuse large B cell lymphomas of different immune-privileged sites (IP-DLBCL) share many clinical and biological features, such as a relatively poor prognosis, preferential dissemination to other immune-privileged sites and deletion of the HLA region, which suggests that IP-DLBCL represents a separate entity. To further investigate the nature of IP-DLBCL, we investigated site-specific genomic aberrations in 16 testicular, 9 central nervous system (CNS) and 15 nodal DLBCL using array-CGH. We also determined minimal common regions of gain and loss. Using robust algorithms, the array-CGH data were combined with gene expression data to explore pathways deregulated by chromosomal aberrations. Keywords: comparative genomic hybridisation, gene expression, tumor type comparison Whole tissue sections of 16 testicular, 9 central nervous system (CNS) and 15 nodal DLBCL were used for isolation of genomic DNA and total RNA. Genomic aberrations were determined using an in house printed CGH array containing ~3700 large genomic insert clones. Gene expression was analyzed on Affymetrix HU133 plus 2.0 oligo arrays. Gene expression data and arrayCGH data were combined using the R program ACE-it.
Project description:Comparison of gene expression profiles from diagnostic samples of diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) to a patient case withsamples of primary and relapsed transformed FL.
Project description:Comparison of gene expression profiles from diagnostic samples of diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) to a patient case withsamples of primary and relapsed transformed FL