3330 results for "*geneti*"

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• Genomic and Epigenomic Features of Primary and Recurrent Hepatocellular Carcinomas

  Intratumor heterogeneity and divergent clonal lineages within and among primary and recurrent hepatocellular carcinomas (HCCs) produce challenges to patient management. We investigated genetic and epigenetic variations within liver tumors, among hepatic lesions, and between primary and relapsing tumors. We performed whole-genome, whole-exome, or targeted capture sequencing analyses HCC specimens collected from multiple tumor regions and matched initial and recurrent tumors to obtain a systematic evaluation of intra- and intertumor genetic heterogeneity in HCC samples and to identify genetic changes associated with tumor progression and recurrence.

  Study EGAS00001002094

• Tracing the origin of disseminated tumor cells in breast cancer using single-cell sequencing

  Background Single-cell micro-metastases of solid tumors often occur in the bone marrow. These disseminated tumor cells (DTCs) may resist therapy and lay dormant or progress to cause overt bone and visceral metastases. The molecular nature of DTCs remains elusive, as well as when and from where in the tumor they originate. Here, we apply single-cell sequencing to identify and trace the origin of DTCs in breast cancer. Results We sequence the genomes of 63 single cells isolated from six non-metastatic breast cancer patients. By comparing the cells DNA copy number aberration (CNA) landscapes with those of the primary tumors and lymph node metastasis, we establish that 53% of the single cells morphologically classified as tumor cells are DTCs disseminating from the observed tumor. The remaining cells represent either non-aberrant ‘normal’ cells or aberrant cells of unknown origin that have CNA landscapes discordant from the tumor. Further analyses suggest that the prevalence of aberrant cells of unknown origin is age-dependent, and that at least a subset is hematopoietic in origin. Evolutionary reconstruction analysis of bulk tumor and DTC genomes enables ordering of CNA events in molecular pseudo-time and traced the origin of the DTCs to either the main tumor clone, primary tumor subclones, or subclones in an axillary lymph node metastasis. Conclusions Single-cell sequencing of bone marrow epithelial-like cells, in parallel with intra-tumor genetic heterogeneity profiling from bulk DNA, is a powerful approach to identify and study DTCs, yielding insight into metastatic processes. A heterogeneous population of CNA-positive cells is present in the bone marrow of non-metastatic breast cancer patients, only part of which are derived from the observed tumor lineages.

  Study EGAS00001002102

• De novo assembly of 150 Danish genomes reveals rich structural complexity

  Most known genetic variation in human genomes has been called from comparison of short reads to the reference genome, an approach biased against finding complex variation. We sequenced 150 individuals from 50 parent-offspring trios with multiple insert-size libraries to very high coverage. We show that each genome could be independently de novo assembled into a small number of high-quality scaffolds (median N50 > 21 Mb), each of quality comparable to long read assemblies while being very cost-effective. We show that our variant call set from comparing de novo assemblies is far more complete in terms of complex variation than previous studies. Importantly, even the complex 4-5 Mb extended MHC region was assembled and resolved into haplotypes, revealing >700kb novel sequence in this important region of the genome, and major parts of the Y chromosome including some palindromes were assembled with high accuracy. Finally, we show that our variant call-set allows for the genotyping of many more complex variants when used as a reference-panel for imputation into SNP-chip data or into previously resequenced genomes.

  Study EGAS00001002108

• North American Brain Expression Consortium (NABEC) Exome Sequencing

  A fundamental challenge in the post-genome era is to understand and annotate the consequences of genetic variation, particularly within the context of human tissues. We describe a set of integrated experiments designed to investigate the effects of common genetic variability on mRNA expression distinct human brain regions. We show that brain tissues may be readily distinguished based on expression profile. We find an abundance of genetic cis regulation mRNA expression. We observe that the largest magnitude effects occur across distinct brain regions. We believe these data, which we have made publicly available, will be useful in understanding the biological effects of genetic variation.

  Study EGAS00001002110

• RNA-sequencing of six Pilocytic astrocytoma tumors

  Pilocytic astrocytoma (PA) is the most common pediatric brain tumor. A recurrent feature of PA is deregulation of the mitogen activated protein kinase (MAPK) pathway most often through KIAA1549-BRAF fusion, but also by other BRAF- or RAF1-gene fusions and point mutations (e.g. BRAFV600E). These features may serve as diagnostic and prognostic markers, and also facilitate development of targeted therapy. The aim of this study was to characterize the genetic alterations underlying the development of PA tumor in six cases, and evaluate methods for fusion oncogene detection. Using a combined analysis of RNA sequencing and copy number variation data we identified a new BRAF fusion involving the 5’ gene fusion partner GTF2I (7q11.23), not previously described in PA. The novel GTF2I-BRAF 19-10 fusion was found in one case, while the other five cases harbored the frequent KIAA1549-BRAF 16-9 fusion gene. Comparing fusion detection methods, Fluorescence in situ hybridization with BRAF break apart probe was the most sensitive method for detection of the two different BRAF rearrangements (GTF2I-BRAF and KIAA1549-BRAF). Our finding of a novel BRAF fusion in PA further emphasis the important role of B-Raf in tumorigenesis of these tumor types. Also, the growing list of BRAF/RAF gene fusions suggests these to be informative tumor markers in molecular diagnostics, which could guide future treatment strategies.

  Study EGAS00001002149

• Whole exome sequencing of Parkinson's disease patients from the United Kingdom

  As part of the International Parkinson's Disease Genomics Consortium, exomes of Parkinson's disease (PD) patients and healthy controls were sequenced to study the genetic etiology of PD. This UK cohort consists of 70 PD patients. Researchers can apply for access to fastq, vcf and binary plink files for this cohort.

  Study EGAS00001002156

• Sequencing of pancreatic cancer primary tumors and metastases

  The extent of heterogeneity of driver gene mutations present in naturally occurring metastases is largely unknown, i.e. treatment-naïve metastatic disease. To address this issue, 60x whole genome sequencing of 26 metastases from 4 patients was carried out. We found that the identical driver gene mutations were present in every metastatic lesion of each patient studied. Passenger gene mutations not known or predicted to have functional consequences accounted for all intratumoral heterogeneity. Even with respect to these passenger gene mutations, the genetic similarity among the founding cells of metastases was markedly higher than that expected for any two cells randomly taken from a normal tissue. The uniformity of driver gene mutations among metastases in the same patient has critical, encouraging implications for the success of future targeted therapies in advanced stage disease.

  Study EGAS00001002186

• An Unusual Genomic Variant of Pancreatic Ductal Adenocarcinoma with an Indolent Clinical Course

  We describe a patient with biopsy-proven locally advanced pancreatic ductal adenocarcinoma (PDA) who underwent a modified course of gemcitabine and stereotactic body radiation therapy. Whole exome sequencing of this patient's tumor revealed a simple genome landscape with no evidence of mutations, copy number changes, or structural alterations in genes most commonly associated with PDA, i.e. KRAS, CDKN2A, TP53 or SMAD4. An analysis of germline DNA revealed no pathogenic variants of significance. Whole exome and whole genome sequencing identified a somatic mutation of RNF213 and an inversion/deletion of CTNNA2 as the genetic basis of this PDA. Although PDA is classically characterized by a predictable set of mutations, these data suggest that alternate genetic paths to PDA may exist, which can be associated with a more indolent clinical course.

  Study EGAS00001002192

• Genome-wide DNA methylation profiles by MeDIP-seq of cord blood cells and cord blood mononuclear cells obtained from twins conceived through in vitro fertilization and naturally conceived controls

  The study included 47 newborn twins conceived though in vitro fertilisation (IVF) and 60 non-IVF-conceived twins from the Peri/postnatal Epigenetic Twins Study (PETS). Cord blood was collected at birth and used to process mononuclear cells. Whole blood cells (WBCs) from cord blood of 98 twins (40 IVF and 58 non-IVF) and cord blood mononuclear cells (CBMCs) of 82 twins (35 IVF and 47 non-IVF) were subjected to DNA methylation profiling. Methylated DNA immunoprecipitation followed by deep sequencing (MeDIP-seq) was applied to generate genome-wide DNA methylation profiles in a total of 180 samples. Single-end reads were mapped onto hg19 using BWA. Methylation levels were quantified using MEDIPS and used to identify IVF-associated differentially methylated regions.

  Study EGAS00001002248

• Illumina Omni5 SNP chip genotyping of MacTel cases and unaffected controls for a genome-wide association study

  Macular telangiectasia type 2 (MacTel) is a rare neurovascular degenerative retinal disease. To identify genetic susceptibility loci for MacTel, we performed a genome-wide association study (GWAS). We genotyped 704 samples, of which 678 have consented to be available here. These samples mainly include MacTel cases but also some unaffected controls (often spouses). The samples were collected through the MacTel Project (funded by the Lowy Medical Research Institute), which includes a registry and extensive clinical analysis to confirm the presence of MacTel in affected individuals. Additional controls were obtained from dbGap [phs000429.v1.p1]. After QC steps, the GWAS utilised 476 cases and 1733 controls of European ancestry.

  Study EGAS00001002249