9296 results for "cancer rna-seq"

in 61.86 milliseconds.

• Enrichment of oral-derived bacteria in inflamed colorectal tumors and distinct associations of Fusobacterium in the mesenchymal subtype

  The association between colorectal cancer (CRC) clinical variables and Fusobacterium, but not other intra-tumoral bacteria, has been extensively studied. Here we leveraged whole-transcriptome sequencing from 807 CRC tumor samples from the AVANT phase III trial to dually characterize tumor gene expression and intra-tumoral bacteria. After stringent filtering, 74 high-confidence taxa were identified. 17 of these species, including 4 Fusobacterium spp., were classified as orally-derived and had a robust signal within right-sided, MSI-H, and BRAF mutant tumors. Across consensus molecular subtypes (CMS), integration of Fusobacterium animalis presence and tumor gene expression revealed that F. animalis had the greatest number of associations in mesenchymal CMS4 tumors, despite an overall lower prevalence than in immune CMS1 tumors. Pathway analysis within CMS4 revealed that F. animalis, but not other highly prevalent species, was uniquely associated with pathways for collagen degradation and formation as well as IL-6 and IL-1 cytokine signaling. These associations could explain in part why Fusobacterium has been previously associated with reduced survival in mesenchymal populations. Overall, this study identified oral-derived bacteria, including Fusobacterium, as broadly more prevalent in inflamed CRC tumors compared to the other subtypes, and the association of intra-tumoral bacteria on tumor gene expression is context- and species-specific.

  Study EGAS00001006757

• Structural variant analysis of homologous recombination-deficient genomes

  Homologous recombination (HR) deficiency causes DNA breaks and cytogenetic aberrations. Paradoxically, the types of DNA rearrangements specifically associated with HR-deficient cancers only minimally impact chromosomal structure. Addressing this, we combined a genome graph analysis of short-read whole genome sequencing (WGS) profiles across thousands of tumors with deep linked-read (LR) WGS of 46 BRCA1 or BRCA2 mutant breast cancers to discover a distinct class of HR deficiency-enriched rearrangements called reciprocal pairs. LR WGS showed that reciprocal pairs with identical rearrangement orientations gave rise to one of two distinct chromosomal outcomes, distinguishable only with long molecule data. While one (cis) outcome corresponded to the copy and pasting of a small segment to a distant site, a second (trans) outcome was a quasi-balanced translocation or multi-megabase inversion with substantial (10kb) duplications at each junction. The full spectrum of reciprocal pair outcomes could be explained by an HR-independent replication restart repair mechanism. LR WGS additionally identified single-strand annealing (SSA) as a BRCA2-deficiency specific repair pathway in human cancers. Replication restart- and SSA-associated SVs improved BRCA1- vs. BRCA2- deficiency classification and identified metastatic cancer cases with favorable chemotherapy responses. Our data reveal classes of BRCA1- and BRCA2-deficiency specific rearrangements as drivers of cytogenetic aberrations in HR deficient cells.

  Study EGAS00001007186

• Molecular analysis of post-colonoscopy CRC (PCCRC)

  Background: Post-colonoscopy colorectal cancers (PCCRCs, i.e. CRC diagnosed after a colonoscopy that excluded cancer) pose a challenge in clinical practice. In a retrospective cohort study, we compared clinical and molecular features of PCCRCs and prevalent CRCs. Methods: PCCRCs were defined according to the WEO classification, as cancers occurring within 10 years after a complete index colonoscopy, which excluded CRC. Whole genome chromosomal copy number changes and mutation status of genes commonly affected in CRC (APC, KRAS, BRAF, FBXW7, PIK3CA, NRAS, SMAD4 and TP53) were examined by low-coverage WGS and targeted sequencing, respectively. MSI and CIMP status were also determined. Results: In total, 122 PCCRCs and 98 prevalent CRCs were examined. PCCRCs are more often located proximally in the colon (p<0.001), non-polypoid appearing (p=0.004), early stage (p=0.009), and poorly differentiated (p=0.006) compared to prevalent CRCs. PCCRCs contain less frequently 18q deletions (p<0.001) than prevalent CRCs. MSI (p=0.029) and CIMP (p=0.014) are more frequently observed in PCCRCs. Conclusion: Although no PCCRC specific pathway could be defined, PCCRCs’ molecular features are more associated with MSI and hypermethylation pathways than canonical CIN pathway. The clinical and molecular features observed in PCCRCs support the hypothesis that sessile serrated lesions and non-polypoid CRNs are contributors to the development of these cancers."

  Study EGAS00001004686

• Whole-Genome and Epigenomic Landscapes of Etiologically Distinct Subtypes of Cholangiocarcinoma

  Cholangiocarcinoma (CCA) is a hepatobiliary malignancy exhibiting high incidence in countries with endemic liver-fluke infection. We analyzed 489 CCAs from 10 countries, combining whole-genome (71 cases), targeted/exome, copy-number, gene expression, and DNA methylation information. Integrative clustering defined 4 CCA clusters-fluke-positive CCAs (clusters 1/2) are enriched in ERBB2 amplifications and TP53 mutations; conversely, fluke-negative CCAs (clusters 3/4) exhibit high copy-number alterations and PD-1/PD-L2 expression, or epigenetic mutations (IDH1/2, BAP1) and FGFR/PRKA-related gene rearrangements. Whole-genome analysis highlighted FGFR2 3' untranslated region deletion as a mechanism of FGFR2 upregulation. Integration of noncoding promoter mutations with protein-DNA binding profiles demonstrates pervasive modulation of H3K27me3-associated sites in CCA. Clusters 1 and 4 exhibit distinct DNA hypermethylation patterns targeting either CpG islands or shores-mutation signature and subclonality analysis suggests that these reflect different mutational pathways. Our results exemplify how genetics, epigenetics, and environmental carcinogens can interplay across different geographies to generate distinct molecular subtypes of cancer.SIGNIFICANCE: Integrated whole-genome and epigenomic analysis of CCA on an international scale identifies new CCA driver genes, noncoding promoter mutations, and structural variants. CCA molecular landscapes differ radically by etiology, underscoring how distinct cancer subtypes in the same organ may arise through different extrinsic and intrinsic carcinogenic processes.

  Study EGAS00001001653

• North Carolina Clinical Genomic Evaluation by NextGen Exome Sequencing (NCGENES)

  North Carolina Clinical Genomic Evaluation by Next-generation Exome Sequencing This study is part of a larger consortium project investigating the validity and best use of next-generation sequencing (in particular, whole exome sequencing, or WES) in clinical care. Participants are patients who were either seen in the UNC Cancer and Adult Genetics Clinic or referred to the study by their physician. They will be approached by their physician or a genetic counselor for recruitment. Once enrolled, a clinical geneticist or genetic counselor will obtain consent and collect blood samples to be analyzed using WES. Results may include information related to a diagnosis and incidental information. Medically actionable incidental findings will be CLIA-certified and returned to participants in a routine genetic counseling session, along with diagnostic findings. Eligible adult participants will be randomized to have the opportunity to choose to get certain types of non-medically actionable incidental findings, as well. Their decisions will be investigated, as will psychosocial and behavioral responses to sequencing and receiving sequencing information. This is a longitudinal, mixed methods study (i.e., multiple assessments pre- and post-return of results, with both quantitative and qualitative methods used to gather data). Because only the quantitative component of the study uses randomization, only measures and procedures associated with that component are included here. The third study release includes data of additional n=189 subjects.

  Study phs000827

• Genetics of Chemotherapy Induced Peripheral Neuropathy in N08C1 and N08CB

  Chemotherapy-induced peripheral neuropathy (CIPN) is a common and potentially dose-limiting toxicity of chemotherapy treatment. CIPN severity varies widely between cancer patients, and previous studies had found evidence of genes and single nucleotide variants (SNV) being associated with CIPN. The goal of this study was to further identify genetic markers and pathways associated with CIPN severity using whole exome sequencing (WES) and whole genome sequencing (WGS) of participants in two clinical studies which collected longitudinal patient-reported outcome (PRO) measures of CIPN. NCCTG/Alliance study N08C1 was a prospective cohort study of the natural history of paclitaxel-associated acute pain syndrome (P-APS) and CIPN. NCCTG/Alliance trial N08CB was a randomized, placebo-controlled trial of calcium and magnesium for prevention of oxaliplatin-induced sensory neuropathy in which the treatment had no significant effect on either acute pain or sensory neuropathy. Both N08C1 and N08CB collected patient assessments of CIPN symptoms before each cycle of chemotherapy using the EORTC QLQ-CIPN20 instrument. For this study, CIPN cases were selected from each of N08C1 and N08CB as those patients with the most severe CIPN symptoms (assessed longitudinally). CIPN controls were selected as those with the least severe symptoms. WGS was obtained for N08C1 samples (WES had been obtained and analyzed previously), and WES was obtained for N08CB samples.

  Study phs001480

• Drug screening of patient-derived organoids from colorectal peritoneal metastases

  Colorectal cancer (CRC) patients with peritoneal metastases (CRPM) have limited treatment options and the lowest CRC survival rates. We trialed the possibility of organoid directed precision treatment for CRPM patients. CRPM organoids (peritonoids) isolated from patients underwent next-generation sequencing and medium-throughput drug panel testing ex vivo to identify specific drug sensitivities for each patient. We measured the utility of such a service including: success of peritonoid generation, time to cultivate peritonoids, reproducibility of the medium-throughput drug testing, and documented changes to clinical therapy as a result of the testing. Peritonoids were successfully generated and validated from 68% (19/28) of patients undergoing standard care. Genomic and drug profiling was completed within 8 weeks and a formal report ranking drug sensitivities was provided to the medical oncology team upon failure of standard care treatment. This resulted in a treatment change for 2 patients, one of whom had a partial response despite previously progressing on multiple rounds of standard care chemotherapy. The barrier to implementing this technology in Australia is the need for drug access and funding for off-label indications. In conclusion, our approach is feasible, reproducible and can guide novel therapeutic choices in this poor prognosis cohort, where new treatment options are urgently needed. This platform is relevant to many solid organ malignancies.

  Study phs002023

• Molecular Characterization of Hemimegalencephaly

  Somatic mutations, in which a fraction of the cells in the body have a deleterious mutation, are well recognized in cancer but only recently appreciated in neurological disease. Given a somatic mutation in a population of progenitor cells, all daughter cells inherit the mutation and are able to express the resultant phenotype as a function of the differentiation program. We recently identified the first de novo somatic mutations in the developing brain in the condition hemimegalencephaly (HME), a catastrophic focal epilepsy condition associated with a malformation of cerebral cortical development (MCD). HME is one of the most severe MCD syndromes, characterized by massive hamartomatous overgrowth of either of the two cerebral hemispheres. Cerebral hemispherectomy is a frequent treatment for refractory epilepsy, allowing the sampling of diseased tissue. By comparing DNA from a diseased brain with DNA from blood/saliva, we identified de novo somatic mutations in PIK3CA, AKT3 or MTOR, part of the mTOR pathway. Mutations were present in 8-40% of sequenced alleles in various brain regions sampled during surgery and in some codons known to activate proteins.• Population informationPatient samples were collected from multiple centers. The population is Caucasian and Hispanic• Molecular technologies employedWhole-exome sequencing• Principal findings of the studyWe were the first to describe mTOR-related and non-mTOR mutations causing hemimegalencephaly, and we described two-hit mutational models to explain the genetic pathogenesis of hemimegalencephaly

  Study phs002156

• Transformation of Dysplasia in Barrett's Esophagus

  Complex chromosomal alterations are a hallmark of advanced cancers but rarely seen in normal tissue. The progression of precancerous lesions to malignancy is often accompanied by increasing complexity of chromosomal alterations that can drive their transformation through focal oncogenic amplifications. However, the etiology and evolution dynamics of these alterations are poorly understood. Here we study chromosomal copy-number evolution in the progression of Barrett's esophagus (BE) to esophageal adenocarcinoma (EAC) by multi-regional whole-genome sequencing analysis of BE samples with dysplasia and microscopic EAC foci. Through haplotype-specific copy-number analysis of BE genome evolution, we identified distinct patterns of episodic copy-number evolution consistent with the outcomes of abnormal mitosis and dicentric chromosome breakage. While abnormal mitosis, including whole-genome duplication, accounts for most chromosome or arm-level copy-number changes, segmental copy-number alterations display signatures of multi-generational evolution of unstable dicentric chromosomes. Continuous evolution of dicentric chromosomes through breakage-fusion-bridge cycles and chromothripsis rapidly increases genomic complexity and diversity among BE cells, culminating in the generation of distinct focal amplifications. These mutational processes enable multiple subclones within small dysplastic areas to undergo parallel transformation to cancer following acquisition of distinct oncogenic amplifications. Our results demonstrate how chromosomal instability drives clonal diversification in precancer evolution and promotes tumorigenesis in primary human samples.

  Study phs002706

• Tobacco exposure and somatic mutations in normal human bronchial epithelium

  That tobacco smoking causes lung cancer is well-established, but we lack quantitative understanding of its effects on genomes of normal bronchial epithelium. We sequenced whole genomes of 632 colonies derived from single bronchial epithelial cells across 16 subjects. Tobacco smoking is the major influence on mutation burden, adding 1000-10,000+ mutations/cell, massively increasing both between-subject and within-subject variance, and generating several distinct signatures of substitutions and indels. A population of cells in subjects with smoking history had mutation burdens equivalent to that expected for never-smokers: these cells lacked tobacco-specific mutational signatures, were four-fold more frequent in ex-smokers than current smokers, and had significantly longer telomeres than their more mutated counterparts. Driver mutations increased in frequency with age, affecting 4-14% of cells in middle-aged never-smokers. In current smokers, ≥25% of cells carried driver mutations and 0-6% cells had 2 or even 3 drivers. Thus, tobacco smoking increases mutation burden, cell-to-cell heterogeneity and driver mutations, but quitting promotes replenishment of bronchial epithelium from mitotically quiescent cells that have avoided tobacco mutagenesis.

  Dataset EGAD00001005193