Project description:Primary plasma cell leukemia (pPCL) is a rare and aggressive variant of multiple myeloma (MM), which is associated with a very poor prognosis. Specific molecular patterns distinguish pPCL in comparison to MM and in relation to main genomic alterations. In the present study, a whole-genome methylation profiling analysis by high-density array revealed a global gene hypomethylation profile in pPCL. Lower methylation levels were particularly observed in the promoter and 5’ untranslated regions (5’UTR), whereas higher levels were evidenced in gene body or 3’ untranslated regions (3’UTR). CpG islands (CGI) resulted largely hypomethylated, whereas higher methylation levels were observed in CGI distal regions. Peculiar differential methylation patterns were identified in association to major chromosomal aberrations and DIS3 mutational status and involved genes playing roles in cell migration, bone metabolism, transcription regulation or DNA damage response. Finally, decreasing methylation levels were evidenced for few genes in association to MM disease progression, from healthy condition to MM and pPCL. Our data may provide new insights into the molecular characterization of pPCL patients, thus being potentially useful in the prognostic stratification or identification of novel molecular targets.
Project description:This SuperSeries is composed of the following subset Series: GSE39380: Genome-wide analysis of primary plasma cell leukemia identifies recurrent imbalances associated with transcriptional Profile alterations (Copy number) GSE39381: Genome-wide analysis of primary plasma cell leukemia identifies recurrent imbalances associated with transcriptional Profile alterations (Expression) Refer to individual Series
Project description:Primary plasma cell leukemia (pPCL) is a rare and very aggressive form of plasma cell dyscrasias. To date, no information of microRNA expression in pPCL has been reported. To investigate the role of miRNAs in pPCL, we analyzed global miRNA expression profiles of highly purified malignant plasma cells from 18 previously untreated patients included in a prospective clinical trial. MiRNA expression patterns were evaluated in the context of the molecular abnormalities of the disease and in comparison with a representative cohort of multiple myeloma (MM) patients. We identified a series of deregulated miRNAs in pPCL (42 up-regulated and 41 down-regulated) which may have a putative role in contributing to tumor progression in MM. Furthermore, we integrated miRNA and gene expression data with computational prediction of miRNA targets, finding that miRNAs differentially expressed between MM and pPCL could regulate genes with important functions in cancer. Overall, our study represents the first attempt to investigate the involvement of miRNAs in pPCL and may contribute to develop functional approaches to investigate the activity of deregulated miRNAs in aggressive forms of plasma cell dyscarsias and their possible role as novel therapeutic targets.
Project description:Primary plasma cell leukemia (pPCL) is a rare and very aggressive form of plasma cell dyscrasias. To date, no information of microRNA expression in pPCL has been reported. To investigate the role of miRNAs in pPCL, we analyzed global miRNA expression profiles of highly purified malignant plasma cells from 18 previously untreated patients included in a prospective clinical trial. MiRNA expression patterns were evaluated in the context of the molecular abnormalities of the disease and in comparison with a representative cohort of multiple myeloma (MM) patients. We identified a series of deregulated miRNAs in pPCL (42 up-regulated and 41 down-regulated) which may have a putative role in contributing to tumor progression in MM. Furthermore, we integrated miRNA and gene expression data with computational prediction of miRNA targets, finding that miRNAs differentially expressed between MM and pPCL could regulate genes with important functions in cancer. Overall, our study represents the first attempt to investigate the involvement of miRNAs in pPCL and may contribute to develop functional approaches to investigate the activity of deregulated miRNAs in aggressive forms of plasma cell dyscarsias and their possible role as novel therapeutic targets. This series of microarray experiments contains the microRNA profiles of purified plasma cells (PCs) obtained from 39 multiple myeloma (MM) and 18 primary plasma cell leukemia (pPCL) at diagnosis. PCs were purified from bone marrow specimens, after red blood cell lysis with 0.86% ammonium chloride, using CD138 immunomagnetic microbeads. The purity of the positively selected PCs was assessed by morphology and flow cytometry and was > 90% in all cases. 500 nanograms of total RNA was processed in accordance with the manufacturer's protocols (Agilent Technologies) to generate Cy3-labelled RNA, which were purified on chromatography columns (Micro Biospin 6, Bio-Rad, Hercules, CA) and then hybridized on an Agilent microarray (G4470B) at 55M-BM-!C for 17 hr in a rotating oven. Images at 5 um resolution were generated using an Agilent scanner G2505B. The Feature Extraction 10.7.3.1 software (Agilent Technologies) was used to obtain the microarray raw-data. The raw gTotalGeneSignal has been recalculated using the procedures described in Agilent Feature Extraction Software version 10.1 manual. Non-human probes, miRNAs flagged as M-CM-^RabsentM-CM-^S (i.e. expressed below background levels) throughout the whole dataset and miRNAs expired according to Sanger miRBase Release 15 (April 2010) were discarded, and a quantile normalization was applied on raw data using the aroma.light package for Bioconducor. The data were then converted to obtain positive values throughout the dataset, at a minimum value of 1, and log2 transformed.
Project description:Primary plasma cell leukaemia (pPCL) is a rare, yet aggressive form of de novo plasma cell tumor, distinguished from secondary PCL (sPCL) which represents a leukemic transformation of pre-existing multiple myeloma (MM). Here, we performed a comprehensive molecular analysis of a prospective series of pPCLs by means of FISH, single nucleotide polymorphism (SNP) array and gene expression profiling (GEP). IGH@ translocations were identified in 87% of pPCL cases, with prevalence of t(11;14) (40%) and t(14;16) (30.5%), whereas the most frequently altered regions were located at 1p (38%), 1q (48%), 6q (29%), 8p (42%), 13q (74%), 14q (71%), 16q (53%) and 17p (35%). A relevant finding of our study was the identification of a minimal biallelical deletion (1.5 Mb) in 8p21.2 encompassing the putative tumor suppressor gene PPP2R2A that was significantly down-regulated in deleted cases. Mutations of TP53 were identified in 4 cases all but one associated with a monoallelic deletion of the gene, whereas activating mutations of BRAF occurred in one case and were absent for N- and K-RAS. To evaluate the influence of allelic imbalances in transcriptional expression we performed an integrated genomic analysis with GEP data, showing a significant dosage effect of genes involved in transcription, translation, methyltransferases activity, apoptosis as well as Wnt and NF-kB signaling pathways. Overall, we provide a compendium of genomic alterations in a prospective series of pPCLs which may contribute to our understanding of this particular form of plasma cell dyscrasia and to better elucidate the mechanisms of tumor progression in MM. This series of microarray experiments contains the genome-wide profiles of 17 primary Plasma Cell Leukemia. 250 nanograms of genomic DNA was processed and, in accordance with the manufacturer's protocols, 90 micrograms of fragmented biotin-labeled DNA were hybridized on GeneChip Human Mapping 250K NspI Arrays (Affymetrix Inc.). The arrays were scanned using the GeneChip Scanner 3000 7G. The images were acquired using Affymetrix GeneChip® Operating Software (GCOS version 1.4). Copy number values for individual SNPs were extracted and converted from CEL files into signal intensities using GTYPE 4.1 and Affymetrix Copy Number Analysis Tool (CNAT 4.0.1) softwares. The raw data for individual SNPs were extracted from CEL files and converted into signal intensities using GTYPE 4.1 and Affymetrix Copy Number Analysis Tool (CNAT 4.0.1) softwares using the Hidden Markov Model algorithm with a genomic smoothing window set to 0. After the pre-processing, piecewise constant estimates of the underlying local DNA copy number (CN) variation was calculated using the DNAcopy Bioconductor package, which looks for optimal breakpoints using circular binary segmentation (CBS). genotyping analysis of 17 primary Plasma Cell Leukemia
Project description:Primary plasma cell leukaemia (pPCL) is a rare, yet aggressive form of de novo plasma cell tumor, distinguished from secondary PCL (sPCL) which represents a leukemic transformation of pre-existing multiple myeloma (MM). Here, we performed a comprehensive molecular analysis of a prospective series of pPCLs by means of FISH, single nucleotide polymorphism (SNP) array and gene expression profiling (GEP). IGH@ translocations were identified in 87% of pPCL cases, with prevalence of t(11;14) (40%) and t(14;16) (30.5%), whereas the most frequently altered regions were located at 1p (38%), 1q (48%), 6q (29%), 8p (42%), 13q (74%), 14q (71%), 16q (53%) and 17p (35%). A relevant finding of our study was the identification of a minimal biallelical deletion (1.5 Mb) in 8p21.2 encompassing the putative tumor suppressor gene PPP2R2A that was significantly down-regulated in deleted cases. Mutations of TP53 were identified in 4 cases all but one associated with a monoallelic deletion of the gene, whereas activating mutations of BRAF occurred in one case and were absent for N- and K-RAS. To evaluate the influence of allelic imbalances in transcriptional expression we performed an integrated genomic analysis with GEP data, showing a significant dosage effect of genes involved in transcription, translation, methyltransferases activity, apoptosis as well as Wnt and NF-kB signaling pathways. Overall, we provide a compendium of genomic alterations in a prospective series of pPCLs which may contribute to our understanding of this particular form of plasma cell dyscrasia and to better elucidate the mechanisms of tumor progression in MM. This series of microarray experiments contains the gene expression profiles of purified plasma cells (PCs) obtained from 21 primary plasma cell leukemia (pPCL) at diagnosis. PCs were purified from bone marrow samples using CD138 immunomagnetic microbeads according to the manufacturer's instructions (MidiMACS system, Miltenyi Biotec); the purity of the positively selected PCs was assessed by morphology and flow cytometry and was > 90% in all cases. 5.5 micrograms of single-stranded DNA target obtained from 100 ng of purified total RNA was fragmented and then labeled using the WT Terminal Labeling Kit according to the standard Affymetrix protocol (GeneChip® Whole Transcript (WT) Sense Target Labeling Assay Manual). The fragmented labeled single-stranded DNA target was hybridized for 16 hours and 30 minutes at 45°C on GeneChip® Gene 1.0 ST array according to the standard Affymetrix protocol. Washing and scanning were performed using GeneChip System of Affymetrix (GeneChip Hybridization Oven 640, GeneChip Fluidics Station 450 and GeneChip Scanner 7G). Log2-transformed expression values were extracted from CEL files and normalized using NetAffx Transcript Cluster Annotations, Release 31 and robust multi-array average (RMA) procedure in Expression Console software (Affymetrix Inc.). The expression values of transcript cluster ID specific for loci representing naturally occurring read-through transcriptions or mapped to more than one chromosomal location were summarized as median value for each sample. gene expression analysis of 21 primary Plasma Cell Leukemia
Project description:To characterize human bone marrow plasma cells that express or lack CD19 on a molecular level, we compared the global gene expression of primary CD38high/CD138+ plasma cells with or without CD19 expression.