3735 results for "*oma"

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• Regulatory Changes in Glioblastoma Brain Tumors and Xenografts Wave 1

  Non-coding elements in our genomes that play critical roles in complex disease are frequently marked by highly unstable RNA species. Sequencing nascent RNAs attached to an actively transcribing RNA polymerase complex can identify unstable RNAs, including those templated from gene-distal enhancers (eRNAs). However, nascent RNA sequencing techniques remain challenging to apply in some cell lines and especially to intact tissues, limiting broad applications in fields such as cancer genomics and personalized medicine. Here we report the development of chromatin run-on and sequencing (ChRO-seq), a novel run-on technology that maps the location of RNA polymerase using virtually any frozen tissue sample, including samples with degraded RNA that are intractable to conventional RNA-seq. We used ChRO-seq to develop the first maps of nascent transcription in 23 human glioblastoma (GBM) brain tumors and patient derived xenografts. Remarkably, >90,000 distal enhancers discovered using the signature of eRNA biogenesis within primary GBMs closely resemble those found in the normal human brain, and diverge substantially from GBM cell models. Despite extensive overall similarity, 12% of enhancers in each GBM distinguish normal and malignant brain tissue. These enhancers drive regulatory programs similar to the developing nervous system and are enriched for transcription factor binding sites that specify a stem-like cell fate. These results demonstrate that GBMs largely retain the enhancer landscape associated with their tissue of origin, but selectively adopt regulatory programs that are responsible for driving stem-like cell properties. We also identified enhancers and their associated transcription factors that regulate genes characteristic of each known GBM subtype, and discovered a core group of transcription factors that control the expression of genes associated with clinical outcomes. This study uncovers new insights into the molecular etiology of GBM and introduces ChRO-seq which can now be used to map regulatory programs contributing to a variety of complex diseases.

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• Whole Exome Characterization of Squamous Cell Lung Cancers (Lung SQCC) from Appalachian Kentucky (APPKY)

  This is a pilot study of squamous cell lung cancer and matched normal tissue pairs collected (convenience sample) from patients from Central Appalachia, in Southeastern Kentucky. This study performed whole exome sequencing on tumor and matched normal DNA samples from 51 lung squamous cell carcinoma (SQCC) subjects from Appalachian Kentucky (AppKY). Somatic genomic alteration profiles were compared between the AppKY and TCGA SQCC cohorts. We found that IDH1 and PCMTD1 had higher mutation rates in AppKY versus TCGA. These findings suggest population differences in the genetics of lung SQCC between AppKY and US populations that have implications for personalized treatment for this disease.

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• Aspirin and Inflammation: Mutations, Genes, Pathways and Prevention in Barrett's Esophagus

  Background: Use of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) has been shown to protect against tetraploidy, aneuploidy, and chromosomal alterations in the metaplastic condition Barrett's esophagus (BE) and to lower the incidence and mortality of esophageal adenocarcinoma (EA). The esophagus is exposed to both intrinsic and extrinsic mutagens resulting from gastric reflux, chronic inflammation and exposure to environmental carcinogens such as those found in cigarettes. Here we test the hypothesis that NSAID use inhibits accumulation of point mutations/indels during somatic genomic evolution in BE. Methods: Whole exome sequences were generated from 82 purified epithelial biopsies and paired blood samples from a cross-sectional study of 41 NSAID users and 41 nonusers matched by sex, age, smoking, and continuous time using or not using NSAIDs. Results: NSAID use reduced overall frequency of point mutations across the spectrum of mutation types, lowered the frequency of mutations even when adjusted for both TP53 mutation and smoking status, and decreased the prevalence of clones with high variant allele frequency. Never smokers who consistently used NSAIDs had fewer point mutations in signature 17, which is commonly found in EA. NSAID users had on average a 50% reduction in functional gene mutations in nine cancer-associated pathways and also had less diversity in pathway mutational burden compared to nonusers. Conclusions: These results indicate NSAID use functions to limit overall mutations on which selection can act and supports a model in which specific mutant cell populations survive or expand better in the absence of NSAIDs. Galipeau PC, et al. Genome Med. 2018 Feb 27;10(1):17. PMID: 29486792.

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• Metastatic Adrenocortical Carcinoma Displays Higher Mutation Rate and Tumor Heterogeneity than Primary Tumors

  We have analyzed 33 human metastatic adrenocortical tumors from 14 patients with advanced metastases and performed whole exome sequencing to identify novel signatures in these tumors. We observed tumor heterogeneity in these tumors coming from the same metastatic tissue site across different patients while the different metastatic tumor sites coming from the same patient are more homogenous in nature.

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• Neoantigen Landscape in a Hypermutated Glioblastoma Arising in a Patient with Germline POLE Deficiency Treated with Checkpoint Blockade Immunotherapy

  Whole genome and exome-based DNA sequencing of germline and tumor specimens from serial samples of patients with glioblastoma. The data set includes several metastases and recurrences from a patient with germline POLE-deficiency. The data reveal extensive tumor heterogeneity, clonal evolution, and genomic responses to immunotherapy.

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• ADAGESIII: Contribution of genotype to glaucoma phenotype in African Americans

  Glaucoma results in vision loss due to damage of the optic nerve that is irreversible if undetected or untreated. The most common form of glaucoma is primary open angle glaucoma (POAG). While glaucoma affects all races, persons of African descent are disproportionately affected; studies show African-Americans (AAs) are about four to five times more likely than Caucasian Americans to develop the disease. Glaucoma is the leading cause of irreversible blindness in Americans of African descent, and the second leading cause in all Americans. The lack of understanding about the etiology of POAG impedes our ability to identify and treat it early in its development. Evidence of genetic contribution in the pathogenesis of POAG is well established. Since POAG tends to run in families, it is critical to identify the genetic basis of the disease in order to develop effective therapies for early intervention. While genome wide association studies (GWAS) for glaucoma have been completed for Caucasian populations, evidence from other studies suggests that a GWAS of glaucoma specific genes to the African-American population will yield unique and important findings for both this population and for glaucoma in general. A better understanding of the relationship among the stage of disease, the rate of change, ancestry, and other important risk factors being tracked in the ongoing African Descent and Glaucoma Study (ADAGES) will allow us to evaluate the relationship between genetics, visual loss and structural damage in this high-risk cohort. The scientific plan for this new study focuses on glaucoma in ∼2058 African-Americans by detailed phenotyping of new subjects, acquisition of samples from both new and established previously phenotyped study subjects for a repository, establishment of a data coordinating center, and genome wide association studies. The recruitment, enrollment, and phenotyping of both established and new subjects occurs at five clinical centers, University of California (UCSD), New York Eye and Ear Infirmary (Mt Sinai) and Columbia University Medical Center, a private practice in the Atlanta area, the University of Alabama at Birmingham, and the Robert Cizik Eye Clinic in Houston, TX. UCSD is also the location for the Data Coordinating Center and the Repository with Robert N. Weinreb as Principal Investigator. LA BioMed at Harbor-UCLA did the genotyping with a GWAS panel of ∼1 million single nucleotide polymorphisms (SNPs) using the Illumina MEGA array under the direction of Jerome Rotter, Ida Chen, and Kent Taylor.

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• Defining T cell States Associated with Response to Checkpoint Immunotherapy in Melanoma

  Checkpoint blockade therapy using antibodies targeting CTLA4, PD1 or PDL1 have changed the way cancer patients with advanced disease are being treated, as evident by their FDA approval in a wide variety of malignancies, and their ability to induce high response rates when compared to conventional therapies (e.g. chemotherapy). However, even in melanoma, despite the high response rate, most patients are refractory to therapy or acquire resistance in 10-12 months. To identify key immunological elements coupled with response or resistance to checkpoint immunotherapy, we performed an unbiased analysis on 16,291 CD45+ immune cells from 32 patients (48 samples) treated with checkpoint therapy (anti-PD1=37; anti-PD1/CTLA4=11), using single cell transcriptomics. Initial unsupervised clustering of all CD45+ cells identified 11 clusters. When examining the association of these clusters with clinical outcome, we found that two clusters (B-cells, p=0.005; memory T-cells, p=0.03) were significantly enriched in responder lesions while 4 clusters (monocytes/macrophages, p=0.003; dendritic cells, p=0.015; exhausted CD8+ T-cells, p=0.005; and exhausted/cell-cycle lymphocytes, 1.3x10-5) are enriched in non-responder lesions. Next, by leveraging our unbiased single cell approach, we identified not only clusters but also specific markers associated with either responder lesions (PLAC8, LTB, LY9, SELL, TCF7, IGKC and CCR7) or non-responder ones (CCL3, CD38, HAVCR2, ENTPD1 and WARS), many of which were not previously reported to be associated with clinical outcome to checkpoint therapy. Due to the importance of CD8+ T-cells in controlling tumors, the significant association of T-cell states with clinical outcome, and their high abundance in melanoma tumors, we next focused our analysis on CD8+ T-cells and identified 2 main clusters CD8_G (with increased expression of genes linked to memory) and CD8_B (enriched for genes linked to cell dysfunction), that were significantly enriched in responder (CD8_G, p=1.4x10-6) and non-responder (CD8_B, p=0.005) lesions, respectively. Since cells with both states coexist in each of the responder and non-responder lesions, we decided to calculate the ratio between the number of cells in these 2 clusters and observed a significant separation between responders (CD8_G/CD8_B>1) and non-responders (CD8_G/CD8_B<1) when looking at all samples, baseline or post samples separately. Similar results were detected when looking at the expression of a single transcription factor, TCF7, in CD8 T-cells in an independent cohort (n=43) using a simple immunofluorescence assay. Additionally, we validated the identity and function of some of the newly identified cell states as well as their epigenetic landscape, and found that cells expressing the inhibitory molecules CD39 and TIM3, on top of being enriched in non-responder lesions, are likely to play a crucial role in T-cell exhaustion in melanoma. Collectively, our study provides extensive unbiased data in human tumors for discovery of predictors and therapeutic targets to checkpoint immunotherapy.

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• National Cancer Institute - Population Structure and Natural Selection in the Epidemiology of Burkitt Lymphoma in East African Children and Minors (EMBLEM) study in Uganda

  A genome-wide analysis of genetic structure, gene flow, and natural selection was conducted in populations in the endemic Burkitt lymphoma (eBL) belt in Ghana and Northern Uganda, both subject to a high incidence of falciparum malaria and eBL. These populations have different ethnolinguistic ancestries and are located 2400 miles apart in sub-Saharan Africa. We characterized genetic composition of these populations in the context of 22 additional African populations and present evidence for gene flow events that occurred in the last 3000 years, possibly related to regional migrations in Western Africa and major migrations involving Nilotic, Cushitic, and Bantu groups. The Ugandan population was comprised of 758 children (mean age ~7 years) from 17 Western Nilo-Saharan tribes. The current dataset includes 561 healthy children and 197 children with eBL from northern Uganda.

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• Genomic Studies for Understanding Etiology of Esophageal Adenocarcinoma (EsophagealAdenocarcinoma_Chinese)

  While the incidence of esophageal adenocarcinoma (EAC) has risen drastically in Western countries over the last 40 years, a similar trend has not been observed for EAC in China. Here we analyzed mutational spectrum, copy number alterations, and structural variants from whole-genome sequencing of ten Chinese EAC tumor samples and their matched normals, and compared them to EAC tumor specimens from Western countries previously reported. The mutational burden in Chinese EAC was significantly lower than that found in EAC from Western countries. The hallmark A>C mutational signature observed at high frequency in EAC from Western countries, which linked to acid reflux, is completely absent in Chinese samples. Furthermore, none of Chinese samples showed evidence of chromothripsis and genome doubling that often found in EAC from Western countries. In summary, Chinese EAC tumor samples revealed distinct genomic profiles and signatures, suggesting that Chinese EAC may arise from a different etiological pathway.

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• Integrative Analysis of Lung Adenocarcinoma in Never Smokers

  We performed whole genome sequencing of lung cancers from never smoker subjects from Institut universitaire de cardiologie et de pneumologie de Québec - Université Laval (IUCPQ-UL) (N=125), Université Côte d'Azur (Nice) (N=47), the Environment And Genetics in Lung cancer Etiology (EAGLE) study (N=27), Yale University (N=22), and Moffitt Cancer Cente (N=11).

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