3773 results for "*oma"

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• Biallelic DICER1 mutations in sporadic pleuropulmonary blastoma

  Pleuropulmonary blastoma (PPB) is an extremely rare pediatric malignancy in the lung, whose pathogenesis is poorly understood, except for recent reports of frequent germline heterozygous DICER1 mutations. To investigate the genetic basis of PPB, we performed whole-exome sequencing in 7 representative PPB cases, followed by targeted deep sequencing in 12 cases with PPB. DICER1 mutations were found in 11/12 cases. Biallelic DICER1 mutations were common in PPB, in which RNase IIIb domain mutations were found in all cases with or without nonsense/frameshift mutations and were somatic in all evaluable cases. A majority of cases had mutated DICER1 alleles in germline with or without an additional somatic mutation in the remaining allele, while other cases had exclusively somatic mutations involving the RNase IIIb domain. TP53 deletions/mutations were detected in 8/12 cases. Our results highlight a unique role of the RNase IIIb domain mutations and TP53 inactivation in PPB pathogenesis.

  Study EGAS00001000662

• Integrated genomic characterization of adrenocortical carcinoma

  Adrenocortical carcinomas (ACC) are aggressive cancers originating in the cortex of the adrenal glands. Despite the overall poor prognosis, ACC outcome is heterogeneous. CTNNB1 and TP53 mutations are frequent in these tumors, but the complete spectrum of genetic changes remains undefined. Exome sequencing and SNP array analysis of 45 ACC revealed recurrent alterations in known drivers (CTNNB1, TP53, CDKN2A, RB1, MEN1) and genes not previously reported to be altered in ACC (ZNRF3, DAXX, TERT and MED12), which were validated in an independent cohort of 77 ACC. The cell-surface transmembrane E3 ubiquitin ligase ZNRF36 was the gene the most frequently altered (21%), and appears as a potential novel tumor suppressor gene related to the ß-catenin pathway. Our integrated genomic analyses led to the identification of two distinct molecular subgroups with opposite outcome. The C1A group of poor outcome ACC was characterized by numerous mutations and DNA methylation alterations, whereas the C1B group with good prognosis displayed a specific deregulation of two miRNA clusters. Thus, aggressive and indolent ACC correspond to two distinct molecular entities, driven by different oncogenic alterations.Array based dataset for this study has been made public at:http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE49280.

  Study EGAS00001000665

• FACS sorting of ploidy populations in an undifferentiated soft tissue sarcoma for RRBS

  Groups of cells belonging to different ploidy populations (based on PI staining) were collected from an undifferentiated soft tissue sarcoma. The different ploidy populations underwent RRBS, after which copy number signatures for the ploidy-sorted populations and the bulk population were extracted.

  Study EGAS00001006143

• Recurrent epimutations activate gene body promoters in primary glioblastoma

  Aberrant DNA hypomethylation may play an important role in the growth rate of glioblastoma (GBM), but the functional impact on transcription remains poorly understood. We assayed the GBM methylome with MeDIP-seq and MRE-seq, adjusting for copy number differences, in a small set of non-glioma CpG island methylator phenotype (non-G-CIMP) primary tumors. Recurrent hypomethylated loci were enriched within a region of chromosome 5p15 that is specified as a cancer amplicon and also encompasses TERT, encoding telomerase reverse transcriptase, which plays a critical role in tumorigenesis. Overall, 76 gene body promoters were recurrently hypomethylated, including TERT and the oncogenes GLI3 and TP73. Recurring hypomethylation also affected previously unannotated alternative promoters, and luciferase reporter assays for three of four of these promoters confirmed strong promoter activity in GBM cells. Histone H3 lysine 4 trimethylation (H3K4me3) ChIP-seq on tissue from the GBMs uncovered peaks that coincide precisely with tumor-specific decrease of DNA methylation at 200 loci, 133 of which are in gene bodies. Detailed investigation of TP73 and TERT gene body hypomethylation demonstrated increased expression of corresponding alternate transcripts, which in TP73 encodes a truncated p73 protein with oncogenic function and in TERT encodes a putative reverse transcriptase-null protein. Our findings suggest that recurring gene body promoter hypomethylation events, along with histone H3K4 trimethylation, alter the transcriptional landscape of GBM through the activation of a limited number of normally silenced promoters within gene bodies, in at least one case leading to expression of an oncogenic protein.

  Study EGAS00001000685

• Validation of a targeted sequencing panel for multiple myeloma

  Study EGAS00001006164

• Small molecule inhibitors of LOXL synergize with 5-AZA to restore erythropoiesis in myeloid neoplasms

  Objectives: Bone marrow (BM) stroma and microenvironmental factors in the BM milieu of myeloid neoplasms are increasingly being recognized as novel perspective therapeutic targets. Lysyl oxidases (LOX/LOXL) are crucial enzymes that cross-link collagen and contribute to the deposition of aberrant stiff extracellular matrix (ECM) in the BM of patients with myelodysplastic syndromes (MDS) and myeloproliferative neoplasms (MPN). Here, we studied whether inhibition of LOX/LOXL enzymes produced by BM-derived MSCs favors the differentiation of MDS/MPN hematopoietic stem cell and progenitor cells (HPSCs) and enhances the effects of 5-azacytidine (5-AZA). Methods: Primary co-cultures of MSCs and HPSCs were established from n=31 MDS/MPN patients and treated with the pan-LOX/LOXL inhibitor PXS-5505, 5-AZA or the combination of both for 4 days. At the end of co-culture, HSPC differentiation was assessed by CFU assays and flow cytometry. In some of the experiments, MSCs monolayers were pre-treated or not with PXS-5505 for 6 days and decellularized using 20 mM ammonia. Subsequently, autologous HSPCs were cultured on ECM matrices in the presence of 5-AZA or PXS-5505 + 5-AZA combination with or without inhibitors of integrin signaling such as blebbistatin, Y-27632 and αvβ3-integrin blocking antibodies. Patient-derived xenografts (PDX) were established in NSG mice based on intrafemoral co-injection of HSPCs and autologous MSCs. PDX were treated with 3 cycles of 5-AZA (75 mg/m2), PXS-5505 (30 mg/kg on alternate days for the duration of 5-AZA treatment) or combination of both. Results: MSCs of MDS and MPN patients displayed significant overexpression of LOX/LOXL transcripts as compared to healthy age-matched controls. Remarkably, LOX/LOXL inhibition in MSCs/HSPCs co-cultures increased erythroid differentiation of patient HSPCs that had suboptimal or no response to 5-AZA alone. From a total of n=31 advanced stage MDS/MPN patients, n=11 (35.5%) responded to the combination treatment, which was evidenced by a significant increase of CD235a+CD45- erythroid cell production compared to 5-AZA/PXS/untreated arms (p<0.05). Of note, combination treatment with 5-AZA + PXS-5505 facilitated differentiation of CD235+ erythroid progenitors from HSPCs sub-clones with low mutational VAFs. The presence of MSCs was necessary for the effects of the combination treatment and required direct cell contacts between MSCs and HSPCs. Moreover, PXS-5505-mediated alterations of the ECM composition alone were sufficient to induce erythroid differentiation. Inhibition of integrin-mediated signaling using blebbistatin, Y-27632 and αvβ3-integrin antibodies completely abrogated the effects of PXS-5505 induced erythroid differentiation. In vivo, the combination of PXS-5505 + 5-AZA favored erythroid differentiation of HSPCs and confirmed the in-vitro results. The combination treatment of 5-AZA + PXS-5505 induced the greatest reduction of disease burden as assessed by decrease of spleen indexes, total engraftment rates, BM fibrosis and mutational VAF profiles. Conclusions: The combination of 5-AZA + LOX/LOXL inhibitor PXS-5505 in MDS and MPN synergistically restores erythropoietic differentiation of primary HSPCs. The effect is dependent of contact interaction between HSPCs and niche components, such as MSCs and MSCs-derived ECM. Our data propose a strong rationale for a BM niche targeted combination treatment with 5-AZA + PXS-5505 in transfusion dependent MDS and MPN, which will be assessed in forthcoming clinical trials.

  Study EGAS00001006174

• Study of pediatric hepatocellular carcinoma caused by bile salt export pump deficiency

  Hepatocellular carcinoma (HCC) is almost invariably associated with an underlying inflammatory state, whose direct contribution to the acquisition of critical genomic changes is unclear. We mapped the acquired genomic alterations in human and mouse HCCs induced by defects in hepatocyte biliary transporters, which expose hepatocytes to bile salts and cause the onset of chronic inflammation that develops into cancer. In both human and mouse cancer genomes we found few somatic point mutations with no impairment of cancer genes, but instead massive gene amplification and rearrangements. This genomic landscape differs greatly from that of virus- and alcohol-associated liver cancer. Copy number gains preferentially occurred at late stages of cancer development and frequently targeted the MAPK signaling pathway, and in particular direct regulators of JNK. The pharmacological inhibition of JNK retarded cancer progression in the mouse. Our study demonstrates that intrahepatic cholestasis leading to hepatocyte exposure to bile acids and inflammation promotes cancer through genomic modifications that can be clearly distinguished from those determined by other etiological factors.

  Study EGAS00001000749

• Primary Neuroblastoma Circle-seq

  We generated Circle-seq data for primary neuroblastoma to describe the landscape of extrachromosomal circular DNA in neuroblastoma.

  Study EGAS00001004797

• Genomic catastrophes frequently arise in esophageal adenocarcinoma and drive tumorigenesis.

  Oesophageal adenocarcinoma (EAC) incidence is rapidly increasing in Western countries. A better understanding of EAC underpins efforts to improve early detection and treatment outcomes. While large EAC exome sequencing efforts to date have found recurrent loss-of-function mutations, oncogenic driving events have been underrepresented. Here we use a combination of whole-genome sequencing (WGS) and single-nucleotide polymorphism-array profiling to show that genomic catastrophes are frequent in EAC, with almost a third (32%, n=40/123) undergoing chromothriptic events. WGS of 22 EAC cases show that catastrophes may lead to oncogene amplification through chromothripsis-derived double-minute chromosome formation (MYC and MDM2) or breakage-fusion-bridge (KRAS, MDM2 and RFC3). Telomere shortening is more prominent in EACs bearing localized complex rearrangements. Mutational signature analysis also confirms that extreme genomic instability in EAC can be driven by somatic BRCA2 mutations. These findings suggest that genomic catastrophes have a significant role in the malignant transformation of EAC.

  Study EGAS00001000750

• Genomic analysis of Smoothened inhibitor resistance in basal cell carcinoma

  Smoothened inhibitors are currently being investigated for the treatment of several cancers. Vismodegib is approved for the treatment of locally advanced and metastatic basal cell carcinoma (BCC). The majority of BCC patients treated with vismodegib experience significant clinical benefit, however, a small number of patients develop resistance. Knowledge of resistance mechanisms can generate predictive biomarkers and is critical for the design of additional therapeutic strategies aimed at circumventing resistance. To investigate mechanisms of resistance to vismodegib in BCC we sequenced and profiled biopsies from patients who initially responded to treatment and subsequently progressed on drug.We find that resistance is associated with re-activation of the Hedgehog (Hh) pathway through diverse mechanisms, including concurrent copy number alterations in the downstream Hh pathway components SUFU and GLI2, as well as novel SMO mutations that reduce sensitivity to vismodegib. The latter fall into two classes: those that activate SMO and those that directly affect the vismodegib-binding pocket. Additionally, we observe evidence of clonal selection of SMO mutations and intra-tumor heterogeneity of resistance mechanisms, which implies diverse and combinatorial strategies are required to overcome resistance.

  Study EGAS00001000845

• Integrated genetic and epigenetic analysis defines novel molecular clusters in rhabdomyosarcoma

  Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in childhood. To unravel the genetic/epigenetic basis of RMS, we studied 60 RMS cases using whole exome/transcriptome sequencing, copy number (CN) profiling, and DNA methylome analysis. Based on DNA methylation patterns, RMS was clustered into 4 distinct subtypes, which exhibited remarkable correlation with mutation/CN profiles, histological phenotypes, and clinical behaviors. A1 and A2 subtypes, especially A1, largely corresponded to alveolar histology with frequent PAX3/7 fusions and alterations in cell cycle regulators. In contrast, mostly showing embryonal histology, both E1 and E2 subtypes were characterized by high frequency of CN alterations and/or allelic imbalances, FGFR4/RAS/AKT pathway mutations and PTEN mutations/methylation and in E2, also by p53 inactivation. Despite generally poor prognosis in RMS, patients in E1 cluster exceptionally showed excellent prognosis. Our results highlight the close relationship between DNA methylation status and gene mutations and biological behavior in RMS.

  Study EGAS00001000884

• Genomic analyses of gynecologic carcinosarcomas reveal frequent mutations in chromatin remodeling genes

  Malignant Mixed Müllerian Tumors, also known as carcinosarcomas, are rare tumors of gynecological origin. Here we perform whole exome analyses of 22 tumors using massively parallel sequencing to determine the mutational landscape of this tumor type. On average, we identify 43 mutations per tumor, excluding four cases with a mutator phenotype that harbored inactivating mutations in mismatch repair genes. In addition to mutations in TP53 and KRAS, we identify genetic alterations in chromatin remodeling genes, ARID1A and ARID1B, in histone methyltransferase MLL3, in histone deacetylase modifier SPOP, and in chromatin assembly factor BAZ1A, in nearly two thirds of cases. Alterations in genes with potential clinical utility are observed in more than three quarters of the cases and included members of the PI 3-kinase and homologous DNA repair pathways. These findings highlight the importance of the dysregulation of chromatin remodeling in carcinosarcoma tumorigenesis and suggest new avenues for personalized therapy.

  Study EGAS00001000941

• Genomic analysis of seminomas

  This study looks at the genomic landscape of seminomas, based on exome sequencing data and SNP array data. Eight seminoma tumors and their matched normal DNAs were exome sequenced on Illumina platforms. The same samples were also processed on Affymetrix SNP 6.0 arrays.

  Study EGAS00001000943

• An RCOR1 loss-associated gene expression signature identifies a prognostically significant DLBCL subgroup

  Effective treatment of diffuse large B cell lymphoma (DLBCL) is plagued by heterogeneous responses to standard therapy, and molecular mechanisms underlying unfavorable outcomes in lymphoma patients remain elusive. Here, we profiled 148 genomes with 91 matching transcriptomes in an R-CHOP-treated DLBCL cohort to uncover molecular subgroups linked to treatment failure. Systematic integration of high-resolution genotyping arrays and RNA-seq data revealed novel deletions in RCOR1 to be associated with unfavorable progression free survival (P = 0.001). Integration of expression data from the clinical samples with data from RCOR1 knockdowns in the lymphoma cell lines KM-H2 and Raji yielded an RCOR1 loss-associated gene signature comprising of 233 genes. This signature identified a subgroup of patients with unfavorable overall survival (OS) (P = 0.023). The prognostic significance of the 233-gene signature for OS was reproduced in an independent cohort comprising of 195 R- CHOP treated patients (P = 0.039). Additionally, we discovered that within the IPI low risk group, the gene signature provides additional prognostic value that was independent of the cell-of-origin phenotype. Taken together, we present a novel and reproducible molecular subgroup of DLBCL, impacting risk-stratification of R- CHOP treated DLBCL patients and revealing a new avenue for therapeutic intervention strategies.

  Study EGAS00001001000

• Spatial heterogeneity in medulloblastoma

  Spatial heterogeneity of transcriptional and genetic markers between physically isolated biopsies of a single tumor poses major barriers to the identification of biomarkers and the development of targeted therapies that will be effective against the entire tumor. We analyzed the spatial heterogeneity of multiregional biopsies from 35 patients, using a combination of transcriptomic and genomic profiles. Medulloblastomas (MBs), but not high-grade gliomas (HGGs), demonstrated spatially homogeneous transcriptomes, which allowed for accurate subgrouping of tumors from a single biopsy. Conversely, somatic mutations that affect genes suitable for targeted therapeutics demonstrated high levels of spatial heterogeneity in MB, malignant glioma, and renal cell carcinoma (RCC). Actionable targets found in a single MB biopsy were seldom clonal across the entire tumor,which brings the efficacy of monotherapies against a single target into question. Clinical trials of targeted therapies for MB should first ensure the spatially ubiquitous nature of the target mutation.

  Study EGAS00001001014

• Targeted Gene Panel for 171 PTCLs

  Mature T-cell lymphomas, including peripheral T-cell lymphoma (PTCL) and extranodal NK/T-cell lymphoma (NKTL), represent a heterogeneous group of non-Hodgkin lymphomas with dismal outcomes and limited treatment options. To determine the extent of involvement of the JAK/STAT pathway in this malignancy, we performed targeted capture sequencing of 188 genes in this pathway in 171 PTCL and NKTL cases. A total of 272 nonsynonymous somatic mutations in 101 genes were identified in 73% of the samples, including 258 single-nucleotide variants and 14 insertions or deletions. Recurrent mutations were most frequently located in STAT3 and TP53 (15%), followed by JAK3 and JAK1 (6%) and SOCS1 (4%). A high prevalence of STAT3 mutation (21%) was observed specifically in NKTL. Novel STAT3 mutations (p.D427H, E616G, p.E616K, and p.E696K) were shown to increase STAT3 phosphorylation and transcriptional activity of STAT3 in the absence of cytokine, in which p.E616K induced programmed cell death-ligand 1 (PD-L1) expression by robust binding of activated STAT3 to the PD-L1 gene promoter. Consistent with these findings, PD-L1 was overexpressed in NKTL cell lines harboring hotspot STAT3 mutations, and similar findings were observed by the overexpression of p.E616K and p.E616G in the STAT3 wild-type NKTL cell line. Conversely, STAT3 silencing and inhibition decreased PD-L1 expression in STAT3 mutant NKTL cell lines. In NKTL tumors, STAT3 activation correlated significantly with PD-L1 expression. We demonstrated that STAT3 activation confers high PD-L1 expression, which may promote tumor immune evasion. The combination of PD-1/PD-L1 antibodies and STAT3 inhibitors might be a promising therapeutic approach for NKTL, and possibly PTCL.

  Study EGAS00001002740

• The Berlin (BLN) panel of glioblastoma cell lines: RNAseq of human gliomasphere cell lines and matched parental tumors

  We generated a panel of nine glioma stem-like cell lines under serum-free cell culture conditions from human glioblastoma samples. In addition to clinical annotation, MR imaging and histological characterization of the parental tumor, as well as xenograft studies of tumorigenecity, transcriptomic profiling of tumor/cell line pairs by RNA sequencing has been performed.

  Study EGAS00001001167