3773 results for "*oma"

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• Molecular and Clonal Evolution in Recurrent Metastatic Gliosarcoma

  We present a rare case of a 37-year-old woman who was initially diagnosed with IDH wild-type gliosarcoma in the frontal lobe and later developed two local recurrences and extracranial metastases to the vertebral and pelvic bones. In order to understand the clonal relationships between the four tumor instances and the origin of metastasis, we performed whole genome sequencing of the intracranial tumors and the tumor located in the right iliac bone. Mutational and copy number profile comparisons of the metastatic to intracranial tumors highlighted a high similarity in molecular profile, but contrasting evidence regarding the origin of the metastasis. Subclonal reconstruction suggested a parallel evolution of the recurrent tumors, and that the metastatic tumor was largely derived from the first recurrence. We conclude that metastasis in glioma can be a late event in tumorigenesis.

  Study EGAS00001004076

• Phased whole genome sequencing of 10 melanoma samples

  We have sequenced 10 melanoma samples using 10X linked reads technology to obtain phased whole genome sequence data. Using this data, we created diploid personalized genomes for each sample and aligned functional genomics data obtained from the same samples in order to find allele specific events (such as allele-specific binding and allele-specific chromatin accessibility).

  Study EGAS00001004136

• Cancer immune control needs senescence induction by Stat1 dependent cell cycle regulator pathways in tumours

  Immune checkpoint bloackade (ICB)-based or natural cancer immune responses largely eliminate tumours. Yet, they require additional mechanisms to arrest those cancer cells that are not rejected. Cytokine-induced senescence (CIS) can stably arrest cancer cells, suggesting that interferon-dependent induction of senescence-inducing cell cycle regulators is needed to control those cancer cells that escape from killing. Here we report in two different cancers sensitive to T cell-mediated rejection, we show that deletion of the senescence-inducing cell cycle regulators p16Ink4a/p19Arf (Cdkn2a) or p21Cip1 (Cdkn1a) in the tumour cells abrogated both, the natural and the ICB-induced cancer immune control. Also in humans, melanoma metastases that progressed rapidly during ICB have losses of senescence-inducing genes and amplifications of senescence inhibitors. Metastatic cells also resist CIS. Such genetic and functional alterations are infrequent in metastatic melanomas regressing during ICB. Thus, activation of tumour-intrinsic, senescence-inducing cell cycle regulators is required to stably arrest those cancer cells that escape from eradication.

  Study EGAS00001004151

• The role of the mammalian SWI/SNF chromatin remodeling complex in neuroendocrine prostate cancer

  We sought to determine the effects of SMARCA4 and SMARCA2 depletion in prostate cancer cell lines. We performed siRNA-mediated knock-down of SMARCA4 and SMARCA2 in an androgen-sensitive (LNCaP) cell line and in a castration-resistant prostate cancer (CRPC)-adenocarcinoma cell line (22Rv1) and compared global transcriptional alterations using RNA-seq.

  Study EGAS00001004177

• Immuno-genomic landscape of osteosarcoma

  Osteosarcoma is an orphan disease affecting children and young adults that has seen little to no progress in survival outcomes for >30 years. Despite having heavily rearranged genomes, to date, clinical trials with immunotherapy have shown no benefit for patients with osteosarcoma. In this study, we conducted the first multi-platform immune profiling (whole genome, transcriptome, T-cell receptor sequencing, immunohistochemistry and reverse phase protein array) on every available pediatric and adult osteosarcoma patients from our institution (N = 48) with the goal of describing immune features that may contribute to immunotherapy resistance.

  Study EGAS00001004197

• Pancreatic tropism of metastatic renal cell carcinoma

  Renal cell carcinoma (RCC) is characterized by a particularly broad metastatic swath, and enigmatically, when the pancreas is a destination, the disease is associated with improved survival. Intrigued by this observation, we sought to characterize the clinical behavior, therapeutic implications, and underlying biology. While pancreatic metastases (PM) are infrequent, we identified 31 patients across two institutional cohorts and show that improved survival is independent of established prognostic variables, that these tumors are exquisitely sensitive to anti-angiogenic agents and resistant to immune checkpoint inhibitors (ICI), and that they are characterized by a distinctive biology. Primary tumors of patients with PM exhibited frequent PBRM1 mutations, 3p loss, and 5q amplification, along with a lower frequency of aggressive features such as BAP1 mutations and loss of 9p, 14q, and 4q. Gene expression analyses revealed constrained evolution with remarkable uniformity, reduced T-effector gene signatures and increased angiogenesis. Similar findings were observed histopathologically. Thus, RCC metastatic to the pancreas is characterized by indolent biology, heightened angiogenesis, and an uninflamed stroma, likely underlying its good prognosis, sensitivity to anti-angiogenic therapies, and refractoriness to ICI. These data suggest that metastatic organotropism may be an indicator of a particular biology with prognostic and treatment implications for patients.

  Study EGAS00001004208

• Analysis of exonic somatic variants in light-chain amyloidosis (ALA) and ALA concomitant with multiple myeloma

  We aim to provide the very first insight into ALA+MM molecular profiles and compare the results with ALA and with MM. Our detailed study of ALA and ALA+MM represents an important step towards improved understanding of their genetic and transcriptomic background, which is a prerequisite for development of optimal treatment strategies in the future.

  Study EGAS00001004214

• Short and long-read genome sequencing methodologies for somatic variant detection; genomic analysis of a patient with diffuse large B-cell lymphoma

  Recent advances in throughput and accuracy mean that the Oxford Nanopore Technologies (ONT) PromethION platform is a now a viable solution for WGS. New bioinformatic methods have been developed to take advantage of this long read data, however much of the validation of these tools has focussed on calling germline variants (both SNVs and structural variants). Somatic variants are outnumbered many-fold by germline variants and their detection is further complicated due to their frequency varying depending on tumour purity/subclonality. Here, we evaluate the extent to which Nanopore WGS enables genome-wide detection and analysis of somatic variation. We do this through sequencing tumour and germline genomes for a patient with diffuse B-cell lymphoma. We examine the capability of currently available tools for calling somatic variants in ONT data by comparing the data with results from 150bp short-read sequencing of the same samples. We then conduct a detailed analysis of the performance of multiple long-read mappers and structural variant callers for calling large, somatic structural variants (SVs) in ONT data. Our protocol achieved yields of up to 96 mapped Gb per PromethION flow cell with average read lengths of ~5kb. Calling germline SNVs from these data achieved good specificity and sensitivity. However, results of somatic SNV calling highlight the need for the development of specialized joint calling algorithms. Our analysis of structural variants shows that the comparative performance of different tools varies significantly between SV types, and suggest long reads are especially advantageous for calling large somatic deletions and duplications. Finally, we highlight the utility of long reads for phasing clinically relevant variants by using the ONT data to confirm that a somatic 1.6Mb deletion and a p.(Arg249Met) mutation involving TP53 are oriented in trans.

  Study EGAS00001004266

• Mutation signatures in melanocytic nevi reveal characteristics of defective DNA repair

  Nevi are common benign melanocytic neoplasms that can be found on any skin location and share many of the genomic hallmarks of melanoma. In our recent report involving whole-exome sequencing of acquired nevi (Stark et al., 2018), ultra-violet radiation (UVR) related somatic mutation signatures (“signature 7”) (Alexandrov et al., 2013) were frequently observed in all lesions that were located on sun-exposed sites. In the study presented herein, we sought to investigate whether an independent Spanish cohort (Valencia, Spain) of minimally sun exposed nevi had genomic features consistent with our previous findings.

  Study EGAS00001004274

• Multiplexed quantification of four neuroblastoma DNA targets in a single droplet digital PCR reaction

  Evaluation of quadruplex ddPCR-based copy number assessment in blood plasma samples paired with genomic DNA from the corresponding primary neuroblastoma from three patients and comparison with copy numbers determined by duplex and triplex ddPCR and re-analyzed from whole-exome sequencing (WES) data.

  Study EGAS00001004275

• Circulating tumor cells for comprehensive and multiregional non-invasive genetic characterization of multiple myeloma (arrays set)

  Multiple myeloma (MM) patients undergo repetitive bone marrow (BM) aspirates for genetic characterization. Circulating tumor cells (CTCs) are detectable in peripheral blood of virtually all MM cases and are prognostic, but their applicability for non-invasive screening has been poorly investigated. Here, we used next-generation flow cytometry to isolate matched CTCs and BM tumor cells from 42 patients and compare their genetic profile. In 8 cases, tumor cells from extramedullary plasmacytomas were also sorted and whole-exome sequencing performed in the three spatially-distributed clones. Noteworthy, ≥84% mutations present in BM and extramedullary clones were detectable in CTCs. Concordance between BM tumor cells and CTCs was high for chromosome arm-level copy-number alterations (≥94%) though not for translocations (43%). All high-risk genetic abnormalities except one t(4;14) were detected in CTCs whenever present in BM tumor cells. Altogether, these results support CTCs for non-invasive risk-stratification of MM patients based on their numbers and genetic profile.

  Study EGAS00001004314

• Multiregion Whole-Exome Sequencing Uncovers the Genetic Evolution and Mutational Heterogeneity of Early-Stage Metastatic Melanoma.

  Study EGAS00001004320

• Persistent STAG2 mutation in recurrent pediatric glioblastoma

  Similar to their adult counterparts, the prognosis for pediatric patients with high-grade gliomas remains poor. At time of recurrence, treatment options are limited and remain without consensus. This report describes the genetic findings, obtained from whole exome sequencing of a pediatric patient with glioblastoma who underwent multiple surgical resections and treatment with standard chemoradiation, as well as a novel recombinant poliovirus vaccine therapy. Strikingly, despite the variety of treatments, there was persistence of a tumor clone, characterized by a deleterious STAG2 mutation, whose deficiency in pre-clinical studies can cause aneuploidy and aberrant mitotic progression, but remains understudied in the clinical setting. There was near elimination of an EGFR mutated and amplified tumor clone after gross total resection, standard chemoradiation, and poliovirus therapy, followed by the emergence of a persistently STAG2 mutated clone, with rare mutations in PTPN11 and BRAF, the latter composed of a novel deleterious mutation previously not reported in pediatric glioblastoma (p.D594G). This was accompanied by a mutation signature shift towards one characterized by increased DNA damage repair defects, consistent with the known underlying STAG2 deficiency. As such, this case represents a novel report following the clinical and genetic progression of a STAG2 mutated glioblastoma, including treatment with a novel and emerging immunotherapy. Although STAG2 deficiency comprises only a small subset of gliomas, this case adds clinical evidence to existing pre-clinical data supporting a role for STAG2 mutations in tumor formation and resistance to standard therapies.

  Study EGAS00001004340

• Multi-omics profiling of paired primary and recurrent glioblastoma patient tissues

  Despite maximal therapy with surgery, chemotherapy and radiotherapy, glioblastoma multiforme (GBM) patients have a median survival of only 15 months. Almost all patients inevitably experience symptomatic tumor recurrence. A hallmark of this tumor type is the large heterogeneity between patients and within tumors itself which relate to failure of standardized tumor treatment. In this study, tissue samples of paired primary and recurrent GBM tumors were investigated to identify individual factors related to tumor progression.

  Study EGAS00001004345

• Sequencing of an adolescent patient with germline RET mutant alveolar rhabdomyosarcoma

  An adolescent patient presented with an alveolar rhabdomyosarcoma made more unique by the presence of a germline RET mutation ordinarily associated with and a known driver of multiple endocrine neoplasia type 2A (MEN2A) cancer. To better understand the role of this germline RET mutation in the genetics and phenotypic response of this unique alveolar rhabdomyosarcoma, we performed DNA and RNA sequencing of the patients in addition to functional studies on patient-derived cultures and genetically similar similar cell models.

  Study EGAS00001004359

• Molecular stratification of endometrioid ovarian carcinoma predicts clinical outcome

  Endometrioid ovarian carcinoma (EnOC) is an under-investigated type of ovarian carcinoma. Here, we report the largest genomic study of EnOCs to date, performing whole exome sequencing of 112 cases following rigorous pathological assessment. High frequencies of mutation were detected in CTNNB1(43%), PIK3CA(43%), ARID1A(36%), PTEN(29%), TP53(26%) and SOX8(19%), a novel target of recurrent mutation in EnOC. POLE and mismatch repair protein-encoding genes were mutated at lower frequency (6%, 18%) with significant co-occurrence. A molecular taxonomy was constructed using a novel algorithm (PRISTINE), identifying clinically distinct EnOC subtypes: TP53m cases demonstrated greater genomic complexity, were frequently FIGO stage III/IV at diagnosis (48%) and incompletely debulked (44%), and demonstrated inferior survival; conversely, CTNNB1m cases demonstrated low complexity and excellent clinical outcome, were predominantly stage I/II at diagnosis (89%) and completely resected (87%). Tumour complexity provides further resolution within the TP53wt/CTNNB1wt group. Moreover, we identify the WNT, MAPK/RAS and PI3K pathways as good candidate targets for molecular therapeutics in EnOC.

  Study EGAS00001004366

• Whole genome sequencing of glioblastoma reveals enrichment of non-coding constraint mutations in known and novel genes

  Glioblastoma (GBM) has one of the worst five-year survival rates of all cancers. While genomic studies of the disease have been performed, alterations in the non-coding regulatory regions of GBM have largely remained unexplored. We apply whole-genome sequencing (WGS) to identify non-coding mutations, with regulatory potential in GBM, under the hypothesis that regions of evolutionary constraint are likely to be functional, and somatic mutations are likely more damaging than in unconstrained regions.

  Study EGAS00001004379