3311 results for "*geneti*"

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• METABRIC: Data from Batra et al (2021); DNA methylation landscapes of 1538 breast cancers reveal a replication-linked clock, epigenomic instability and cis-regulation

  DNA methylation is aberrant in cancer, but the dynamics, regulatory role and clinical implications of such epigenetic changes are still poorly understood. Here, RRBS-based profiles of 1538 breast tumors and 244 normal breast tissues from the METABRIC cohort are reported, facilitating detailed analysis of DNA methylation within a rich context of genomic, transcriptional, and clinical data. Tumor methylation from immune and stromal signatures are deconvoluted leading to the discovery of a tumor replication-linked clock with genome-wide methylation loss in non-CpG island sites. Unexpectedly, methylation in most tumor CpG islands follows two replication-independent processes of gain (MG) or loss (ML) that we term epigenomic instability. Epigenomic instability is correlated with tumor grade and stage, TP53 mutations and poorer prognosis. After controlling for these global trans-acting trends, as well as for X-linked dosage compensation effects, cis-specific methylation and expression correlations are uncovered at hundreds of promoters and over a thousand distal elements. Some of these targeted known tumor suppressors and oncogenes. In conclusion, the study demonstrates that global epigenetic instability can erode cancer methylomes and expose them to localized methylation aberrations in-cis resulting in transcriptional changes seen in tumors.

  Study EGAS00001004327

• Persistent STAG2 mutation in recurrent pediatric glioblastoma

  Similar to their adult counterparts, the prognosis for pediatric patients with high-grade gliomas remains poor. At time of recurrence, treatment options are limited and remain without consensus. This report describes the genetic findings, obtained from whole exome sequencing of a pediatric patient with glioblastoma who underwent multiple surgical resections and treatment with standard chemoradiation, as well as a novel recombinant poliovirus vaccine therapy. Strikingly, despite the variety of treatments, there was persistence of a tumor clone, characterized by a deleterious STAG2 mutation, whose deficiency in pre-clinical studies can cause aneuploidy and aberrant mitotic progression, but remains understudied in the clinical setting. There was near elimination of an EGFR mutated and amplified tumor clone after gross total resection, standard chemoradiation, and poliovirus therapy, followed by the emergence of a persistently STAG2 mutated clone, with rare mutations in PTPN11 and BRAF, the latter composed of a novel deleterious mutation previously not reported in pediatric glioblastoma (p.D594G). This was accompanied by a mutation signature shift towards one characterized by increased DNA damage repair defects, consistent with the known underlying STAG2 deficiency. As such, this case represents a novel report following the clinical and genetic progression of a STAG2 mutated glioblastoma, including treatment with a novel and emerging immunotherapy. Although STAG2 deficiency comprises only a small subset of gliomas, this case adds clinical evidence to existing pre-clinical data supporting a role for STAG2 mutations in tumor formation and resistance to standard therapies.

  Study EGAS00001004340

• MeDALL Epigenetics group

  Dac EGAC00001000578

• Phylogenetic reconstruction of breast cancer

  The aim of this study was to identify the evolutionary trajectories of metastatic breast cancer. We present whole genome sequencing data (primary tumours, axillary lymph nodes, distant metastasis and matched normal tissues) from 16 breast cancer patients. This work sheds light on the routes on which tumour cells metastasize and their role in disease progression in ER-positive breast cancer.

  Study EGAS00001004356

• Sequencing of an adolescent patient with germline RET mutant alveolar rhabdomyosarcoma

  An adolescent patient presented with an alveolar rhabdomyosarcoma made more unique by the presence of a germline RET mutation ordinarily associated with and a known driver of multiple endocrine neoplasia type 2A (MEN2A) cancer. To better understand the role of this germline RET mutation in the genetics and phenotypic response of this unique alveolar rhabdomyosarcoma, we performed DNA and RNA sequencing of the patients in addition to functional studies on patient-derived cultures and genetically similar similar cell models.

  Study EGAS00001004359

• Genetic diversity and continuity of the population of the UAE

  With high consanguinity rates on the Arabian Peninsula, it would not have been unexpected if the population of the UAE was shown to be relatively homogenous. However, this study of 1,000 UAE nationals, provided a contrasting perspective, one of a relatively heterogeneous population. Located at the apex of Europe, Asia and Africa, the observed diversity could be explained by a plethora of migration patterns since the first Out-of-Africa movement. A strategy to explore the extent of genetic variation of the population of the UAE is presented. The first step involved a comprehensive population stratification study that was instructive for subsequent Whole Genome Sequencing (WGS) of suitable representatives (which is described elsewhere). When this UAE data was compared to previous smaller studies from the region, the findings were consistent with a population that is a diverse and admixed group of people. However, rather than sharp and distinctive clusters, a continuous genotype distribution was observed. The analysis showed a continuous gradient of ancestral populations, suggesting that admixture on the south eastern tip of Arabian Peninsula occurred gradually. When visualized using a unique technique that combined admixture ratios and Principal Component Analysis (PCA), unappreciated diversity was revealed while mitigating projection bias of conventional PCA. The analytical strategy used here highlights the complementary nature of data from genotype array and WGS for anthropological studies. Specifically, genotype array data was instructive to select representative subjects for WGS. Furthermore, from the 2.3 million allele frequencies obtained from genotype arrays, we identified 46,481 loci with allele frequencies that were significantly different with respect to other world populations. This comparison of allele frequencies facilitates variant prioritization in common diseases. In addition, these loci bear great potential as biomarkers in anthropological and forensic studies.

  Study EGAS00001004362

• Whole-genome sequencing of rare disease patients in a national healthcare system

  Most patients with rare diseases do not receive a molecular diagnosis and the aetiologicalvariants and mediating genes for more than half such disorders remain to be discovered. Weimplemented whole-genome sequencing (WGS) in a national healthcare system to streamlinediagnosis and to discover unknown aetiological variants, in the coding and non-coding regionsof the genome. In a pilot study for the 100,000 Genomes Project, we generated WGS data for13,037 participants, of whom 9,802 had a rare disease, and provided a genetic diagnosis to1,138 of the 7,065 patients with detailed phenotypic data. We identified 95 Mendelianassociations between genes and rare diseases, of which 11 have been discovered since 2015and at least 79 are confirmed aetiological. Using WGS of UK Biobank1, we showed that rarealleles can explain the presence of some individuals in the tails of a quantitative red blood cell(RBC) trait. Finally, we reported 4 novel non-coding variants which cause disease through thedisruption of transcription of ARPC1B, GATA1, LRBA and MPL. Our study demonstrates asynergy by using WGS for diagnosis and aetiological discovery in routine healthcare.

  Study EGAS00001004364

• Epigenetic analyses of methylation and nucleosome occupancy in cell-free DNA (cfNOMe)

  Cell-free DNA (cfDNA) has become essential in cancer diagnostics and prenatal testing. We investigate enzymatic cytosine conversion for epigenetic analyses of cfDNA and find that it reliably measures cytosine methylation and nucleosome occupancy. Whereas previously, separate experiments had to be performed to study either epigenetic marking, this approach delivers reliable results for both, enabling more comprehensive and inexpensive epigenetic profiling of cfDNA.

  Study EGAS00001004370

• Genomic study of an AT-AML

  Ataxia Telangiectasia (A-T) is caused by biallelic mutations in ATM and confers predisposition to cancer, with acute myeloid leukaemia (AML) being rarely observed. We investigated an AML arising in an A-T patient for secondary genetic events by performing whole exome sequencing of serial samples over the disease course. AML samples were compared to a reference "germline" sample from a much earlier time point. Goldgraben et al 2020, Pediatric Blood & Cancer

  Study EGAS00001004392

• Search for genetic variants influencing gestational weight gain in type 1 diabetes patients by genome wide association method

  Clinical data suggest that BMI and gestational weight gain (GWG) are strongly interconnected phenotypes, however the genetic basis of the latter is rather unclear. Here we aim to investigate the genetic factors associated with GWG from the perspective of the genetics of obesity.

  Study EGAS00001004408