14308 results for ""Pennsylvania+German"+ACS+study+'Socius'+open+access"

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• HIV-phyloTSI: Subtype-independent estimation of time since HIV-1 infection for cross-sectional measures of population incidence using deep sequence data

  Estimating the time since HIV infection (TSI) at population level is essential for tracking changes in the global HIV epidemic. Most methods for determining TSI give a binary classification of infections as recent or non-recent within a window of several months, and cannot assess the cumulative impact of an intervention. We developed a Random Forest Regression model, HIV-phyloTSI, which combines measures of within-host diversity and divergence to generate continuous TSI estimates directly from viral deep-sequencing data, with no need for additional variables. HIV-phyloTSI provides a continuous measure of TSI up to 9 years, with a mean absolute error of less than 12 months overall and less than 5 months for infections with a TSI of up to a year. It performs equally well for all major HIV subtypes based on data from African and European cohorts. We demonstrate how HIV-phyloTSI can be used for incidence estimates on a population level.

  Study EGAS50000000895

• RTEL1 mutation as a modifier of Dyskeratosis Congenita in a family with a Telomerase RNA (hTR) template mutation and variant telomeric repeats

  Vertebrate telomeres, the sequences protecting the end of linear chromosomes, are composed of conserved hexameric GGTTAG repeats. Here we present a C50>A telomerase RNA template mutation that results in the incorporation of the variant telomeric repeat GTTTAG in a family with dyskeratosis congenita primarily presenting as idiopathic pulmonary fibrosis. The mutant telomerase is characterized by decreased processivity in direct telomerase activity assays and in vivo based on data from Illumina next-generation whole genome sequencing and Oxford Nanopore Technologies long-read telomere sequencing. The latter provided positional mutant repeat information that revealed the inheritance and maintenance of proximal mutant repeats in individuals who did not inherit the template mutation. Additionally, we describe an RTEL1 nonsense mutation that is associated with very short telomeres in progeny harboring wild-type telomerase and inherited mutant telomeric repeats in the absence of overt clinical phenotypes. In contrast, co-inheritance of the RTEL1 nonsense and TERC r.C50>A mutations coincided with severe early-onset DC phenotypes in two individuals.

  Study EGAS50000001644

• Advancing fast in the analysis of circulating tumour DNA

  In cancer patients, solid tumours also release DNA fragments into the blood, and they are called Circulating Tumours DNA (ctDNA). Nowadays, the standard procedure for cancer monitoring is analysis of surgically obtained biopsies. They generate a big amount of material, but the operation is highly invasive and provide medical doctors with a single-time snapshot of the tumours, which are often highly changeable. Analysis of ctDNA, on the other hand, can provide continuous information regarding the tumour itself without the need of invasive procedures. This is why interest in this method is growing, and with it, the need for its technological optimization. Guanhua Zhu and colleagues, at the Genome Institute of Singapore, developed a methodology to quantify ctDNA burden, which means to estimate the amount of tumours derived circulating DNA among all cell-free DNA in the blood of individuals. Their work, published in Nature Communications in april 2021 and summarized in a sketch below, uses state-of-the art methods to analyse cfDNA degradation patterns at promoters and exon regions, to discern it from the DNA coming from the tumours. The bright point of their approach is that simultaneously enable for profiling of actionable cancer mutations and quantitative estimation of ctDNA burden. Their sequencing data of ctDNA has been deposited in the EGA under the accession number EGAS00001004657. This study sums up to a total of 37 of cfDNA and 36 about ctDNA present up to date in the EGA archive. The existence of cfDNA was firstly described back in 2002, while the use of ctDNA analysis in the oncological field exploded only after 2016. The approach is rapidly evolving, moving in parallel with the ever-improving sequencing technologies. Especially, the possibility to obtain high quality sequences from minimal amount of material is a crucial factor. Being able to alleviate cancer patients of disturbing and often slow-recovery procedures, while at the same time improving the quality of diagnosis and disease monitoring seems like a lot to ask. Thankfully, we are blessed with brilliant and dedicated scientists from all around the world who collaborate to make this a reality, sharing their results, knowledge and data.

  Blog advancing-fast-in-the-analysis-of-circulating-tumour-dna

• Fragmentomics Uncover Non-Mutational HRD Features

  Homologous recombination deficiency (HRD) is a key biomarker in prostate cancer (PCa), predicting response to PARP inhibitors and platinum-based therapies. However, current diagnostics often rely solely on BRCA1/2 mutations or genomic scars, missing cases driven by other mechanisms. Tissue-based testing is further limited by tumor heterogeneity and biopsy challenges in metastatic bone disease. Here, we applied a comprehensive multimodal approach to assess HRD in 106 advanced PCa patients using circulating tumor DNA (ctDNA). This included targeted sequencing of homologous recombination repair (HRR) genes, low-pass WGS for genomic instability (sHRD), WES for mutational signatures, and cfDNA fragmentomics and chromatin accessibility profiling. BRCA2 was the most frequently altered gene, often co-occurring with PTEN loss. High sHRD scores correlated with BRCA2/RB1 loss, somatic copy number alterations, and poor survival. HRD tumors showed enrichment of SBS3/ID6 signatures, altered fragment lengths, and reduced accessibility at zinc finger transcription factor sites. These results support ctDNA-based multimodal profiling as a non-invasive strategy for HRD detection and stratification.

  Study EGAS00001008190

• Mutational analysis reveals the origin and therapy-driven evolution of recurrent glioma

  Tumor recurrence is a leading cause of cancer mortality. Therapies for recurrent disease may fail, at least in part, because the genomic alterations driving the growth of recurrences are distinct from those in the initial tumor. To explore this hypothesis, we sequenced the exomes of 23 initial low-grade gliomas and recurrent tumors resected from the same patients. In 43% of cases, at least half of the mutations in the initial tumor were undetected at recurrence, including driver mutations inTP53, ATRX, SMARCA4, and BRAF; this suggests that recurrent tumors are often seeded by cells derived from the initial tumor at a very early stage of their evolution. Notably, tumors from 6 of 10 patients treated with the chemotherapeutic drug temozolomide (TMZ) followed an alternative evolutionary path to high-grade glioma. At recurrence, these tumors were hypermutated and harbored driver mutations in the RB (retinoblastoma) and Akt-mTOR (mammalian target of rapamycin) pathways that bore the signature of TMZ-induced mutagenesis.

  Study EGAS00001000579

• Gene fusion and transcriptomic landscapes of sarcomas

  Sarcoma represents a highly heterogeneous group of tumors. We report here the first unbiased and systematic search for gene fusions and analysis of transcriptomic profiles in 100 monomorphic sarcomas cases using RNA-sequencing profiling. Fusion genes were detected in two thirds of samples. Similarly to fusion genes such as PAX3/7-FOXO1, EWSR1/FUS-ETS, SS18-SSX, BRD3/4-NUTM1 or EWSR1/FUS/TAF15-NR4A3 characterizing well-defined entities, we show that all sarcomas displaying CIC fusions- whatever their fusion partner (being DUX4, NUTM1 or FOXO4) - form a transcriptionally homogeneous group of tumors. Likewise, tumors with either a BCOR fusion (with CCNB3, MAML3 or ZC3H7B partners) or with a BCOR internal duplication form a single biological entity. We also found that EML4-ALK fusions also characterize a homogeneous infantile fibrosarcoma subgroup. In contrast, fusions like VGLL2-NCOA2/CITED2, TMP3/TRP-NTRK1 or ETV6-NTRK3 are observed in more heterogeneous tumors. Finally, we also describe a new group of bone sarcomas characterized by EWSR1- or FUS-TFCP2 fusions.

  Study EGAS00001002189

• Recursive splicing in long vertebrate genes

  Recent studies have shown that expression of many genes with exceptionally long introns in the mammalian brain can be perturbed by regulatory factors linked to neurodevelopmental or neurodegenerative disorders1-3, suggesting unique regulatory mechanisms. Here we identify functional recursive splice sites (RSS) in long introns of genes expressed in the brain. These RSS are highly conserved in genes with extreme length across diverse vertebrate species and permit step-wise removal of long introns via recursive splicing. Recursive splicing requires initial definition of a “recursive exon” that is located downstream of RSS, and most often contains premature stop codons. Moreover, we show that RSS create a splicing switch driven by splice site competition in order to distinguish primary mRNA isoforms from alternative isoforms that are prevalent in long genes. The recursive exon is not detectable in the dominant mRNA isoform due to recursive splicing, but is completely included when cryptic promoters or other cryptic exons are used. Thus, by coupling inclusion of recursive exons with the use of cryptic elements, RSS act to distinguish new mRNA isoforms emerging from long genes.

  Study EGAS00001001170

• Exome-seq, RNA-Seq, SNP array profiling of gastric tumor samples and cell lines.

  Gastric cancer is the second leading cause of worldwide cancer mortality, yet the underlying genomic alterations remain poorly understood. Here we performed exome and transcriptome sequencing and SNP array assays to characterize 51 primary gastric tumors and 32 cell lines. Meta-analysis of the exome data and previously published data sets revealed 24 significantly mutated genes in MSS tumors, and 16 in MSI tumors. More than half of the patients in our collection could potentially benefit from targeted therapies. We identified 55 splice-site mutations accompanied by aberrant splicing products, in addition to mutation-independent differential isoform usage in tumors. The ZAK kinase isoform TV1 is preferentially upregulated in gastric tumors and cell lines relative to normal samples. This pattern is also observed in colorectal, bladder, and breast cancers. Overexpression of this particular isoform activated multiple cancer-related transcription factor reporters, while depletion of ZAK in gastric cell lines inhibited proliferation. These results reveal the spectrum of genomic and transcriptomic alterations in gastric cancer, and identify isoform-specific oncogenic properties of ZAK.

  Study EGAS00001000736

• Illumina HumanCoreExome genotyping data from the British Society for Surgery of the Hand Genetics of Dupuytren’s Disease consortium (BSSH-GODD consortium) collection

  Dupuytren's Disease (DD - OMIM126900) is the most common heritable disorder of connective tissue. It is a fibroproliferative disorder of the palmer fascia, causing flexion contractures of affected digits. DD affects men more commonly than women. DD is an archetypal complex disease, with multiple genetic and environmental factors affecting the final expression of the disease phenotype. The incidence increases with age, and the prevalence of DD is therefore increasing as the UK population ages. Half of all patients present before age 60. DD causes significant functional impairment, and severe contractures can lead to permanent disability. The mainstay of current treatment is surgery, but recurrence and complications are both high. For severe contractures, the only suitable treatment option is amputation. The direct costs to the NHS are high, and underestimate the true economic costs to society. We collected salivary samples from adults in the UK who have had surgery for DD. We have genotyped these samples using the Illumina HumanCoreExome Beadchips. https://research.ndorms.ox.ac.uk/public/dupuytrens/what-is-dupuytrens-disease/

  Study EGAS00001001206

• Engineering of a promoterless anti-viral RNAi hairpin into an endogenous miRNA locus

  Short hairpin RNA (shRNA) expression strategies that allow safe and persistent target mRNA knockdown are key to the success of many in vitro or in vivo RNAi applications. Here, we propose a novel solution which is expression of a promoterless miRNA-adapted shRNA (shmiRNA) from an engineered genomic miRNA locus. For proof-of-concept, we genetically “vaccinated” liver cells against a human pathogen, by using TALEns or CRISPR to integrate an anti-hepatitis C virus (HCV) shmiRNA into the liver-specific miR-122/hcr gene. Reporter assays and qRT-PCR confirmed anti-HCV shmiRNA expression as well as miR-122 integrity and functionality. Specificity and safety of shmiRNA integration were validated via PCR, cDNA and miRNA profiling, and whole genome sequencing. A subgenomic HCV replicon and a full-length reporter virus, but not a Dengue virus control, were significantly impaired in the modified cells. Our original combination of DNA engineering and RNAi expression technologies should benefit numerous applications, from basic miRNA research, to human cell and gene therapy.

  Study EGAS00001001252