3798 results for "*oma"

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• Genetic analysis of HLA and immune escape genes in Diffuse Large B-cell Lymphoma

  Fifty percent of diffuse large B-cell lymphoma (DLBCL) cases lack cell-surface expression of the class-I major histocompatibility complex (MHC-I), thereby escaping immune recognition by cytotoxic T cells. In order to comprehensively identify the mechanisms involved in MHC-I loss, we first performed immunophenotypic analysis of both MHC class-I and -II in 657 cases across the spectrum of B-NHL, revealing that loss of MHC-I, but not MHC-II, is preferentially restricted to DLBCL. We then used whole exome and targeted deep-sequencing to examine genes involved in MHC-I expression in 74 DLBCL samples representative of MHC-I positive and negative cases. We show here that somatic biallelic or monoallelic inactivation of B2M and/or HLA-I is present in 80.9% (34/42) of MHC-I negative tumors. Furthermore, 68.8% (22/32) of MHC-I positive DLBCLs also harbored monoallelic HLA-I genetic alterations (MHC-I positivemono) that lead to allelic imbalance, suggesting allele-specific inactivation. Both MHC-I negative and MHC-I positivemono cases showed a significantly higher mutational burden as well as a higher number of inferred neo-antigens, suggesting co-selection of HLA-I loss and sustained neo-antigen production. Interestingly, the analysis of > 500.000 individuals in two databases revealed homozygosity of germline HLA-I genes in 26-38% of DLBCL patients, a frequency significantly higher than that observed in any other cancer type. In mice, germinal-center B cells lacking HLA-I expression did not progress to lymphoma and were counterselected in the context of oncogene-driven lymphomagenesis, suggesting that additional events are needed to license immune evasion. These results suggest a multi-step process of HLA-I loss including both germ-line and somatic events in DLBCL development, and have direct implications for the pathogenesis and immunotherapeutic targeting of this disease.

  Study EGAS00001005054

• Mutational analysis of an oligoprogressive sarcomatoid hepatocellular carcinoma treated with an immune checkpoint inhibitor.

  In this study, we describe a patient diagnosed with metastatic sarcomatoid hepatocellular carcinoma that showed a remarkable tumor response to Nivolumab, an immune checkpoint inhibitor, followed by an oligoprogression. Molecular analysis of the primary tumor in addition to a bone and brain metastasis was performed and we were able to identify driver genetic alterations indicating a possible role in the tumorigenesis process besides some alterations that may be associated with metastasis.

  Study EGAS00001005064

• Genomic Landscape of Malignant Peripheral Nerve Sheath Tumor-like Melanoma

  Malignant peripheral nerve sheath tumor (MPNST)-like melanoma is a rare malignancy with overlapping characteristics of both neural sarcoma and melanoma. The genomics of MPNST-like melanoma have not been previously described. This study provides the results of whole exome and transcriptome sequencing analysis of 8 samples from 6 patients with confirmed diagnosis of MPNST-like melanoma. This study demonstrates that MPNST-like melanoma shares oncogenic alterations common to both cutaneous melanoma and MPNST, and also suggests that MPNST-like melanoma harbors unique genomic and transcriptomic alterations.

  Study EGAS00001005065

• Whole-exome sequencing of hepatocellular carcinoma biopsies (proteogenomic study)

  We performed a proteogenomic analysis of hepatocellular carcinomas (HCCs) across clinical stages and etiologies to define the deregulated pathways and heterogeneity among HCCs. We identified pathways that are differentially regulated on the genomic, transcriptomic, proteomic and phosphoproteomic levels. Integrative clustering identified HCC subgroups that show distinct regulation of biological processes, metabolic reprogramming and kinase activation.

  Study EGAS00001005073

• Transcriptome sequencing of hepatocellular carcinoma biopsies (proteogenomic study)

  We performed a proteogenomic analysis of hepatocellular carcinomas (HCCs) across clinical stages and etiologies to define the deregulated pathways and heterogeneity among HCCs. We identified pathways that are differentially regulated on the genomic, transcriptomic, proteomic and phosphoproteomic levels. Integrative clustering identified HCC subgroups that show distinct regulation of biological processes, metabolic reprogramming and kinase activation.

  Study EGAS00001005074

• Anal SCC cell line and parent tumour comparative whole exome sequencing

  1) To perform whole exome sequencing on a panel of five human anal squamous cell carcinoma lines and their respective parent tumours. 2) To perform a comparative analysis between the lines and their parent tumours. 3) Specifically assess the somatic nucleotide variants, copy number variants, mutational burden and mutational signatures.

  Study EGAS00001005077

• Hermansky-Pudlak syndrome type 1 causes impaired anti-microbial immunity through a pathogenic lipid metabolism-mTOR circuit - 10x Genomics scRNAseq

  Mendelian diseases that present with immune-mediated disorders can provide insights into the molecular mechanisms that drive inflammation. Hermansky-Pudlak syndrome (HPS) types 1 and 4 are caused by defective vesicle trafficking involving the BLOC-3 complex. The presence of inflammatory complications such as Crohn’s disease-like inflammation and lung fibrosis in these patients remains enigmatic. Using mass cytometry we observe an augmented inflammatory monocyte compartment in HPS1 patient peripheral blood that may be associated with a TNF - and IL-1α-dominated cytokine dysregulation. HPS1 patient monocyte-derived macrophages express an inflammatory TNF-OSM mRNA gene signature and changes in lipid metabolism. Using stimulation experiments and lysosomal proteomics we show that defective lipid metabolism drives RAB32-dependent mTOR signaling, facilitated by the accumulation of mTOR on lysosomes. This pathogenic circuit translates into aberrant bacterial clearance, which can be rescued with mTORC1 inhibition. We reveal that a pathogenic lipid-mTOR signaling circuit acts as a metabolic checkpoint for defective anti-microbial activity. This mechanism may be relevant to the complex pathology of HPS1 patients featuring macrophage lipid accumulation, granuloma formation, defective anti-microbial activity and tissue inflammation. Lastly, this circuit may be present in a wider group of disorders with defective lipid metabolism and cholesterol accumulation.

  Study EGAS00001005098

• WES of clonally related neuroblastoma and teratoma

  Mature teratomas are usually benign tumors that rarely undergo malignant transformation. We report an advanced neuroblastoma arising in a mature teratoma of the ovary. Whole-exome sequencing identified extensive copy-neutral LOH in both neuroblastoma and teratoma elements, suggesting that the neuroblastoma evolved from the teratoma.

  Study EGAS00001005116

• Engineering large chromosomal deletions by CRISPR-Cas9

  Arm-level chromosomal deletions are a prevalent and defining feature of cancer. A high degree of tumor-type and subtype specific recurrencies suggest a selective oncogenic advantage. However, due to their large size it has been difficult to pinpoint the oncogenic drivers that confer this advantage. Suitable functional genomics approaches to study the oncogenic driving capacity of arm-level deletions are limited. Here we present an effective technique to engineer arm-level deletions by CRISPR-Cas9 and create isogenic cell line models. We simultaneously induce double-strand breaks (DSBs) at two ends of a chromosomal arm and select the cells that have lost the intermittent region. Using this technique, we induced arm-level deletions on chromosome 11q (65 MB) and chromosome 6q (53 MB) in neuroblastoma cell lines. Such isogenic models enable further research on the role of arm-level deletions in tumor development and growth, and their possible therapeutic potential.

  Study EGAS00001005134

• Whole genome sequence and RNA-seq data from paired tumour and germline samples from mesothelioma patients.

  Malignant pleural mesothelioma (MPM) has a poor overall survival with few treatment options. Whole genome sequencing (WGS) combined with RNA sequencing (RNA-seq) analysis of the immune features of MPM offers the prospect of identifying changes that could inform future clinical trials. We analysed somatic mutation and RNA-seq data from 229 MPM samples, including 58 MPM samples that had undergone WGS from our own institutions, together with other published data. This combined analysis identified somatic driver genes, including newly identified candidate genes. Whole genome doubling was a frequent event that correlated with shorter survival. Mutational signature analysis revealed dominant signatures and showed that defects in homologous recombination repair were infrequent in our cohort. Within the tumour immune environment we identified high M2 macrophage infiltrate linked with MMP2, MMP14, TGFB1 and CCL2 expression, representing an immunosuppressive environment. A small subset of samples had a higher proportion of CD8 T cells and a high cytolytic score, suggesting a ‘hot’ immune environment which is independent of the somatic mutations. We propose that our findings on genomic changes and subtypes of immune microenvironments may influence therapeutic planning in the future.

  Study EGAS00001005196