3794 results for "*oma"

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• Integrative genomic analysis identifies key pathogenic mechanisms in primary mediastinal large B-cell lymphoma

  Primary mediastinal large B-cell lymphoma (PMBL) represents a clinically and pathologically distinct subtype of large B-cell lymphomas. Furthermore, molecular studies, including global gene expression profiling, have provided evidence that PMBL is more closely related to classical Hodgkin lymphoma (cHL). Although targeted sequencing studies have revealed a number of mutations involved in PMBL pathogenesis, a comprehensive description of disease-associated genetic alterations and perturbed pathways is still lacking. Here, we performed whole-exome sequencing of 95 PMBL tumors to inform on oncogenic driver genes and recurrent copy number alterations. The integration of somatic gene mutations with gene expression signatures provides further insights into genotype-phenotype interrelation in PMBL. We identified highly recurrent oncogenic mutations in the JAK-STAT and NF-kB pathways, and provide additional evidence of the importance of immune evasion in PMBL (CIITA, CD58, B2M, CD274, PDCD1LG2). Our analyses highlight the IRF-pathway as a putative novel hallmark with frequent alterations in multiple pathway members (IRF2BP2, IRF4, IRF8). In addition, our integrative analysis illustrates the importance of JAK1, RELB and EP300 mutations driving oncogenic signaling. The identified driver genes were significantly more frequently mutated in PMBL as compared to diffuse large B-cell lymphoma, whereas only a limited number of genes were significantly different between PMBL and cHL, emphasizing the close relationship between these entities. Our study, performed on a large cohort of PMBL, highlights the importance of distinctive genetic alterations for disease taxonomy with relevance for diagnostic work-up and therapeutic decision-making.

  Study EGAS00001003746

• Small_molecule_inhibitors_in_melanoma___Kenski___Kong___WES

  Small-molecule inhibitors targeting the most commonly activated pathway in melanoma, MAPK pathway (either alone or in combination) are already given to melanoma patients for few years, and initially reduce tumour burden dramatically, eventually melanomas become resistant and tumours progress while on treatment. Resistance to this treatment occurs by acquisition of additional mutations or other alterations that affect the mitogen-activated protein kinase (MAPK) pathway by either direct or indirect signalling. Many resistance mechanisms somehow lead to reactivation of extracellular signal-regulated kinase (ERK), thereby restoring signalling of the oncogenic BRAF/MEK/ERK pathway. In addition, PI3K pathway activation contributes to resistance to BRAF inhibition. Less frequent but equally important to the phenomenon of targeted drug resistance is the observation that B15–20% of BRAF mutant melanoma patients fail to respond to BRAF inhibition already early on treatment, owing to intrinsic resistance. These patients have little therapeutic options, unless immunotherapy can be given. To better understand the resistance mechanisms in MAPK inhibitor-treated melanoma patients and melanoma biology, our lab generated a big panel of MAPK inhibitor resistant melanoma cell lines by continuous drug exposure. The understanding of the genetic landscape and gene expression as well as cross resistance to other treatment regimens, and other aspects of melanoma biology such as phenotype switch, will allow us to better exploit new therapeutic strategies for melanoma patients.

  Study EGAS00001002863

• Genomics_of_acral_lentiginous_melanoma

  Melanoma is the most aggressive type of skin cancer, causing about 75% of dermatological cancer deaths. Acral lentiginous melanoma (ALM) is the most common subtype of melanoma in admixed Latin American populations, but very few tumour genomes and exomes, all from European-descent individuals, have been analysed across several studies. Because of this, the genomic landscape of ALM is mostly unknown. Our aim in this project is to define this landscape and identify driver somatic alterations by whole-exome sequencing a collection of ALM germline/tumour paired FFPE samples from the National Cancer Institute of Mexico.

  Study EGAS00001003740

• Whole Genome Sequencing of HCC

  The French ICGC project on liver tumors is coordinated by Pr Jessica Zucman-Rossi and funded by Inca (French Institute for Cancer). The aim of the present project is to identify the catalog of somatic and germline mutations in liver tumors using whole genome (WGS) and whole exome sequencing (WGS), integrated with DNA methylation and RNA sequencing (RNA-seq) data. The present series corresponds to 24 whole genome sequencing (12 Tumoral/Non-tumoral pairs). Hepatocellular carcinoma (HCC) accounts for more than 90% of liver cancers, and is a major health problem. It is the 3rd cause of cancer-related mortality. Advances in genomic analyses have formed a comprehensive understanding of different underlying pathobiological layers resulting in hepatocarcinogenesis. Thus, the development of next-generation sequencing technologies has made it possible to generate more comprehensive catalogues of somatic alteration events (single nucleotide substitutions, structural variations, and epigenetic changes) in liver cancer genome than ever before.

  Study EGAS00001002888

• 2014_Lung_sq_WES

  Purpose Lung squamous cell carcinoma (SqCC) is the second most prevalent type of lung cancer. Currently, no targeted-therapeutics are approved for treatment of this cancer, largely due to lack of systematic understanding of the molecular parthenogenesis of the disease. To identify therapeutic targets and comparatively analyze them in lung SqCC, we probed somatic alterations of Korean lung SqCC. Patients and Methods We performed massively parallel whole-exome sequencing of 104 Korean lung SqCC patients’ samples with matched normal samples. In addition, copy number analysis and transcriptome analysis were conducted for a subset of these samples. Clinical association with cancer-specific somatic alterations was investigated.

  Study EGAS00001002844

• WGS/RNA-seq pair of an inflammatory hepatocellular adenoma (IHCA)

  A 49 years old female patient consulted for diarrhea, rectal bleeding and lower limbs edema and was diagnosed with systemic AA amyloidosis. An inflammatory hepatocellular adenoma was further identified and resected, resulting in the improvement of amyloidosis-related symptoms. Molecular analyses of the tumor tissue revealed a somatic chromosome rearrangement responsible for interleukin-6 mRNA stabilization leading to an inflammatory acute response with serum amyloid A protein production by both neoplastic and normal hepatocytes.

  Study EGAS00001003025

• Whole Exome Sequencing in Multiple Myeloma

  By whole exome sequencing (WES) our group observed the accumulation of mutations in receptor tyrosine kinases (RTKs), adhesion molecules and their effectors and developed a signaling network that was affected by at least one mutation in almost 100% of MM patients and by more than one mutation in around 50% of MM patients which we decided to call inter- and intra-individual pathway redundancy. Interestingly, the extension of our WES dataset to 67 primary MM samples with correspond normal tissue which were collected at the Medizinische Klinik and Poliklinik II in Würzburg within the frame of the CRU216 has tentatively led to the designation of three molecular subgroups based on their mutation profile: "adhesion only", "adhesion & downstream" and "RTK & adhesion & downstream

  Study EGAS00001003227

• Structure and evolution of double minutes in diagnosis and relapse brain tumors

  Double minute chromosomes are extrachromosomal circular DNA fragments frequently found in brain tumors. To understand their evolution, we characterized the double minutes in paired diagnosis and relapse tumors from a pediatric high-grade glioma and four adult glioblastoma patients. We determined the full structures of the major double minutes using a novel approach combining multiple types of supporting genomic evidence. Among the double minutes identified in the pediatric tumor, only one carrying EGFR was maintained at high abundance in both samples, whereas two others were resent in only trace amounts at diagnosis but abundant at relapse, and the rest were found either in the relapse sample only or in the diagnosis sample only. For the EGFR-carrying double minutes, we found a secondary somatic deletion in all copies at relapse, after erlotinib treatment, but this was rare at diagnosis, suggesting potential resistance to the EGFR inhibitor. This mutation caused an in-frame RNA transcript to skip exon 16, a novel transcript absent in EST database and in about 700 brain tumors that we reviewed. We observed similar patterns involving longitudinal copy number shift of double minutes in another four pairs (diagnosis / relapse) of adult glioblastoma. Overall, in three of five paired tumor samples, we found that although the same oncogenes were amplified at diagnosis and relapse, they were amplified on different double minutes. Our results suggest that double minutes readily evolve, increasing tumor heterogeneity rapidly. Understanding patterns of double minute evolution can shed light on future therapeutic solutions to brain tumors carrying such variants.

  Study EGAS00001003212

• Uveal melanoma patient with germline MBD4 nonsense mutation

  There is currently no effective treatment for metastasised uveal melanoma (UM). Recently, it was reported that a UM patient was responsive to checkpoint inhibitor (CI) treatment, due to a high tumour mutation burden correlated with a germline loss-of-function MBD4 mutation. Here, we report on another UM patient who carried an MBD4 germline nonsense variant (p.Leu563Ter) and her tumour showed a 5-fold higher than average mutation burden. We confirmed the association between germline loss-of-function variant in MBD4 and CI response. The patient experienced stable disease (10 months) and survived two years with metastatic disease, which is twice as long as median survival. Additionally, the frequency of MBD4 loss-of-function variants in reported UM cohorts was >20 times higher than in an aggregated population genome database (P < 5x10-5), implying a potential role as UM predisposition gene. These findings provide a strong basis for the inclusion of MBD4 in screening of potential UM-prone families as well as stratification of immunotherapy.

  Study EGAS00001003362

• Probabilistic cell type assignment of single-cell transcriptomic data reveals spatiotemporal microenvironment dynamics in human cancers

  Single-cell RNA sequencing (scRNA-seq) has transformed biomedical research, enabling decomposition of complex tissues into disaggregated, functionally distinct cell types. For many applications, investigators wish to identify cell types with known marker genes. Typically, such cell type assignments are performed through unsupervised clustering followed by manual annotation based on these marker genes, or via "mapping" procedures to existing data. However, the manual interpretation required in the former case scales poorly to large datasets, which are also often prone to batch effects, while existing data for purified cell types must be available for the latter. Furthermore, unsupervised clustering can be error-prone, leading to under- and over- clustering of the cell types of interest. To overcome these issues we present CellAssign, a probabilistic model that leverages prior knowledge of cell type marker genes to annotate scRNA-seq data into pre-defined and de novo cell types. CellAssign automates the process of assigning cells in a highly scalable manner across large datasets while simultaneously controlling for batch and patient effects. We demonstrate the analytical advantages of CellAssign through extensive simulations and exemplify real-world utility to profile the spatial dynamics of high-grade serous ovarian cancer and the temporal dynamics of follicular lymphoma. Our analysis reveals subclonal malignant phenotypes and points towards an evolutionary interplay between immune and cancer cell populations with cancer cells escaping immune recognition.

  Study EGAS00001003452