Search Results - EGA European Genome-Phenome Archive

Immediate Postoperative Minimal Residual Disease Detection with MAESTRO Predicts Recurrence and Survival in Head and Neck Cancer Patients Treated with Surgery

We selected 24 patients with locally advanced head and neck squamous cell carcinoma (HNSCC) who were surgically treated. MAESTRO, our ultrasensitive, tumor-informed, mutation enrichment sequencing assay, was applied in a pooled format (MAESTRO-Pool) to plasma samples collected from these patients at baseline (pre-op) and postoperatively. We show that detection of circulating tumor DNA (ctDNA) 1 to 9 days after surgery is associated with significantly worse survival. Many plasma samples also had tumor fractions detected below 100 parts-per-million, the detection limit for first-generation commercial assays, highlighting the need for more sensitive ctDNA assays. Here we provide whole genome sequencing of matched tumor biopsy and normal germline DNA from 24 patients that were used to identify somatic single nucleotide variants (SNVs) to be tracked using our MAESTRO-Pool assay.

Study phs003981

Beacon v2 and Federated EGA, part of the GDI project Starter Kit to enable access to genomic and phenotypic data across borders

The European Genomic Data Infrastructure project has released a ‘Starter Kit’ based on the rare disease and cancer proof-of-concepts from the Beyond 1 Million Genomes (B1MG) project. The Starter Kit, freely available to any interested parties, contains a set of software applications and components co-developed by the 20 GDI nodes and based on open community standards from the Global Alliance for Genomics and Health (GA4GH). Products in the Starter Kit give all countries the technical capability to access synthetic genomic and phenotypic data across borders. The image above shows the full workflow of the GDI Starter Kit user journey. The dotted circles are not included in the Starter Kit yet The EGA’s work is represented in the Starter Kit with Beacon v2 and Federated EGA among the software applications and components. About Beacon v2 Beacon is a protocol for data discovery. This API allows the search of genomic variants and associated information without breaching the datasets privacy. The European Genome-phenome Archive (EGA) is a key contributor to the Beacon v2 Protocol, the Beacon v2 Reference Implementation (B2RI) and the EGA Beacon(s). About Federated EGA The Federated EGA network offers a tool for data storage and sharing. Officially launched in 2022, this network of connected resources enables transnational discovery of and access to human omics data for research, while also respecting jurisdictional data protection regulations. The Federated EGA Onboarding Website contains all the information related to the establishment of a Federated Node.

Blog beacon-v2-and-federated-ega-part-of-the-gdi-project-starter-kit

WGS dataset for Genomic rearrangements in Pediatric Cancer

Dataset EGAD00001008272

Sequence data to study genomic CNVs that drive apoptotic resistance and relapses on immune checkpoint inhibitors

This project investigates the genomic mechanisms underlying acquired resistance to immune checkpoint inhibitors (ICIs) across tumor types, addressing the critical clinical problem of treatment relapses where the molecular basis remains poorly understood. Through integrative genomic analyses of longitudinal clinical melanomas, functional CRISPR-Cas9 screens, and human and murine melanoma models, the study demonstrates that copy-number variant (CNV)-driven subclonal evolution is a primary driver of clinical relapses. The research identifies resistance-driver genes targeted by CNVs, including pro-apoptotic gene deletions and anti-apoptotic gene amplifications, which collectively downregulate apoptotic priming in resistant cells. The findings establish that modulating the apoptotic threshold can prevent or reverse ICI resistance, positioning CNV evolution as a key driver of acquired resistance and identifying apoptotic regulation as a therapeutic target to combat resistance evolution.

Study EGAS50000001055

Investigation_of_mutational_signatures_associated_with_DNMT3A_deficiency_

Mutational signatures have been shown to be attributable to specific genetic contexts, such as mutations in DNA repair genes. DNMT3A is a DNA methyltransferase that helps maintain the DNA methylation pattern in a site-specific manner and may participate in DNA repair or the stress response. We have identified an adult individual who is a germline mosaic for a DNMT3A mutation. We have obtained clonal lymphoblastoid cells (LCLs) from the subject representing both WT and mutant lines grown in the same individual for >50 years. These clones represent a unique opportunity to examine the mutational impact of the DNMT3A mutation in a well-controlled setting. Our goal is to perform WGS on whole blood, representing the pool, as well as several WT and several mutant clones, in order to investigate the contribution of DNMT3A to mutation rates and signatures.

Study EGAS00001002329

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

CRLF2_sequencing_project_

I hope to gain insight into novel genetic aberrations present in these patients that will highlightimportant pathways that are involved in this subtype of leukaemia. It would be interesting to see ifthe mutations and pathways that are activated are consistent between the patients, or differencesare observed dependent upon whether the patient has the translocation or the PAR1 deletion. Ofnote is the high association with either numerical gains of chromosome X or numerical/structuralabnormalities of chromosome 21 (Down syndrome, iAMP21) in patients with CRLF2 deregulation. Ihope to find abnormalities linking chromosomes X and 21 to CRLF2 deregulation in BCP‐ALL. Byincluding the three patients that are normal for CRLF2, but have consistent genetic abnormalitiesfound in the experimental cohort, I expect to find genetic differences between these two groupsthat will help us to identify novel molecular targets specific to CRLF2 deregulation.

Study EGAS00001000080

Autozygosity_pilot___Pakistani_from_Birmingham

The offspring of first cousin marriages have ~6% of their genome autozygous, i.e. homozygous identical by descent, or even more if there was further consanguinity in their ancestry. In the UK there are large populations with very high first cousin marriage rates of 50-80%. Sequencing the exomes of a sample of these individuals has the potential both to support genetic health programmes in these populations, and to provide genetic research information about rare loss of function mutations. This pilot study based on existing British-Pakistani cohort samples from Birmingham will identify homozygous individuals for almost all variants down to an allele frequency around 1%, plus individuals carrying hundreds of new homozygous rare loss-of-function variants, and will support development of community relations and ethics for a wider study currently being designed. The data deposited in the EGA consist of low coverage whole exome sequencing on these samples.

Study EGAS00001000511

CRLF2_sequencing_project_Exomes

I hope to gain insight into novel genetic aberrations present in these patients that will highlight important pathways that are involved in this subtype of leukaemia. It would be interesting to see if the mutations and pathways that are activated are consistent between the patients, or differences are observed dependent upon whether the patient has the translocation or the PAR1 deletion. Of note is the high association with either numerical gains of chromosome X or numerical/structural abnormalities of chromosome 21 (Down syndrome, iAMP21) in patients with CRLF2 deregulation. I hope to find abnormalities linking chromosomes X and 21 to CRLF2 deregulation in BCP‐ALL. By including the three patients that are normal for CRLF2, but have consistent genetic abnormalities found in the experimental cohort, I expect to find genetic differences between these two groups that will help us to identify novel molecular targets specific to CRLF2 deregulation.

Study EGAS00001000081

Genomic and transcriptomic determinants of therapy resistance and immune landscape evolution during anti-EGFR treatment in colorectal cancer

Despite biomarker stratification, the anti-EGFR antibody cetuximab is only effective against a subgroup of colorectal cancers (CRC). This genomic and transcriptomic analysis of the cetuximab resistance landscape in 35 RAS wild-type CRCs identified associations of NF-1 and non-canonical RAS/RAF-aberrations with primary resistance and validated transcriptomic CRC-subtypes as non-genetic predictors of benefit. 64% of biopsies with acquired resistance harbored no genetic resistance drivers. Most of these had switched from a cetuximab-sensitive transcriptomic subtype pre-treatment to a fibroblast- and growth factor-rich subtype at progression. Fibroblast-supernatant conferred cetuximab resistance in vitro, confirming a major role for non-genetic resistance through stromal remodeling. Cetuximab treatment increased cytotoxic immune infiltrates and PDL1 and LAG3 immune-checkpoint expression, potentially providing opportunities to treat cetuximab-resistant CRCs with immunotherapy.

Study EGAS00001003367

Reliable detection of somatic mutations in solid tissues by laser-capture microdissection and low-input DNA sequencing

Somatic mutations accumulate in healthy tissues as we age, giving rise to cancer and potentially contributing to ageing. To study somatic mutations in non-neoplastic tissues, we developed a series of protocols to sequence the genomes of small populations of cells isolated from histological sections. Here, we describe a complete workflow that combines laser-capture microdissection (LCM) with low-input genome sequencing, whilst circumventing the use of whole-genome amplification (WGA). The protocol is subdivided broadly into 4 steps: tissue processing, LCM, low-input library generation and mutation calling and filtering. The tissue processing and LCM steps are provided as general guidelines which may require tailoring based on the specific requirements of the study at hand. Our protocol for low-input library generation utilises enzymatic rather than acoustic fragmentation to generate WGA-free whole-genome libraries. Finally, the mutation calling and filtering strategy has been adapted from previously published protocols to account for artefacts introduced via library creation. To date, we have used this workflow to perform targeted and whole-genome sequencing of small populations of cells (typically 100-1,000 cells) in thousands of microbiopsies from a wide range of human tissues. The low-input DNA protocol is designed to be compatible with liquid handling platforms and make use of equipment and expertise standard to any core sequencing facility. However, obtaining low-input DNA material via LCM requires specialized equipment and expertise. The entire protocol from tissue reception through whole-genome library generation can be accomplished in as little as a week, though 2-3 weeks would be a more typical turnaround time.

Dataset EGAD00001006088

hereditary BrEAst Case CONtrol study (BEACCON)

The BEACCON study aimed to address the lack of power of previous studies to identify novel BC predisposition genes by performing extensive sequencing in 12,000 women (11,511 analysed following exclusions) and further enhancing power by using an ‘extreme phenotype’ design with enrichment of familial non-BRCA1 and BRCA2 cases, compared with a control population of older women with ongoing confirmation of cancer-free status at June 2019. Three-quarters of the 1303 candidate genes screened were selected based on empiric evidence from local (69 multi-case BC families) or international whole exome sequencing studies, and the remainder were included to provide detailed coverage of functional pathways with established associations with BC.

Dataset EGAD00001007025

META-PRISM

A pan-cancer cohort of 1031 patients resistant to systemic therapies or with no approved therapeutic options. It includes whole-exome sequencing of 571 tumor and matched-normal samples, and transcriptome sequencing of 947 tumor samples. Biopsies were taken at entry into precision medicine trials, often after diagnosed resistance. Comprehensive clinical information is available for all patients and include patient age at biospy, tumor primary site and histological subtype, biopsy site, treatments received prior to biopsy, blood assessment results at biopsy, metastatic sites at biopsy, and survival time from the biopsy date.

Dataset EGAD00001009684

sWGS of core biopsies from localized breast cancer patients

Paired end shallow whole genome sequencing (sWGS) data for the identification of genomewide somatic copy number alterations (SCNA) and the estimation of tumor fractions.

Dataset EGAD00001008397

Distinct evolutionary trajectories of primary high grade serous ovarian cancers revealed through spatial mutational profiling

High-grade serous ovarian cancer (HGSC) is characterized by poor outcome, often attributed to emergence of treatment-resistant sub-clones. We sought to measure the degree of genomic diversity within primary, untreated HGSC to examine the natural state of tumor evolution prior to therapy. We performed exome sequencing, copy number analysis, targeted amplicon deep sequencing and gene expression profiling on thirty-one spatially and temporally separated HGSC tumor specimens (six patients) including ovarian masses, distant metastases, and fallopian tube lesions. We found widespread intra-tumoral variation in mutation, copy number, and gene expression profiles, with key driver alterations in genes present in only a subset of samples (e.g. PIK3CA, CTNNB1, NF1). On average, only 51.5% of mutations were present in every sample of a given case (range: 10.2% to 91.4%), with TP53 as the only somatic mutation consistently present in all samples. Complex segmental aneuploidies, such as whole genome doubling, were present in a subset of samples from the same individual, with divergent copy number changes segregating independently of point mutation acquisition. Reconstruction of evolutionary histories showed one patient with mixed HGSC and endometrioid histology with common etiologic origin in the fallopian tube and subsequent selection of different driver mutations in the histologically distinct samples. In this patient, we observed mixed cell populations in the early fallopian tube lesion, indicating diversity arises at early stages of tumorigenesis. Our results reveal that HGSC exhibit highly individual evolutionary trajectories and diverse genomic tapestries prior to therapy, exposing an essential biological characteristic to inform future design of personalized therapeutic solutions and investigation of drug resistance mechanisms.

Dataset EGAD00001000974

Distinct evolutionary trajectories of primary high grade serous ovarian cancers revealed through spatial mutational proﬁling

High-grade serous ovarian cancer (HGSC) is characterized by poor outcome, often attributed to the emergence of treatment-resistant subclones. We sought to measure the degree of genomic diversity within primary, untreated HGSCs to examine the natural state of tumour evolution prior to therapy. We performed exome sequencing, copy number analysis, targeted amplicon deep sequencing and gene expression profiling on 31 spatially and temporally separated HGSC tumour specimens (six patients), including ovarian masses, distant metastases and fallopian tube lesions. We found widespread intratumoural variation in mutation, copy number and gene expression profiles, with key driver alterations in genes present in only a subset of samples (eg PIK3CA, CTNNB1, NF1). On average, only 51.5% of mutations were present in every sample of a given case (range 10.2 to 91.4%), with TP53 as the only somatic mutation consistently present in all samples. Complex segmental aneuploidies, such as whole-genome doubling, were present in a subset of samples from the same individual, with divergent copy number changes segregating independently of point mutation acquisition. Reconstruction of evolutionary histories showed one patient with mixed HGSC and endometrioid histology, with common aetiologic origin in the fallopian tube and subsequent selection of different driver mutations in the histologically distinct samples. In this patient, we observed mixed cell populations in the early fallopian tube lesion, indicating that diversity arises at early stages of tumourigenesis. Our results revealed that HGSCs exhibit highly individual evolutionary trajectories and diverse genomic tapestries prior to therapy, exposing an essential biological characteristic to inform future design of personalized therapeutic solutions and investigation of drug-resistance mechanisms

Dataset EGAD00001000669

CAGE-seq analysis of osteoblast derived from cleidocranial dysplasia human induced pluripotent stem cells

Non-coding RNAs (ncRNAs) comprise a major portion of transcripts and serve an essential role in biological processes. Although the importance of major transcriptomes in osteogenesis has been extensively studied, the function of ncRNAs in human osteogenesis remains unclear. Previously, we developed hiPSCs from patients with cleidocranial dysplasia (CCD) caused by runt-related transcription factor 2 (RUNX2) haploinsufficiency. To gain insight into ncRNAs in osteogenesis, we surveyed differential ncRNA expression profiling and promoter differences of RUNX2 using patient-specific iPSCs and cap analysis gene expression (CAGE) technology to define the promoter landscape. Revertant iPSCs (Rev1 iPSCs) edited by CRISPR/Cas9 system to harbor mutation-corrected RUNX2 exhibited increased proximal promoter expression of RUNX2, while CCD iPSCs did not. We identified 2271 ncRNA genes with altered expression levels before and after differentiation, 31 of which showed at least 20-fold higher expression in Rev1 iPSCs. Bioinformatic analysis also categorized AC007392.3, LINC00379, RP11-122D10.1, and RP11-90J7.2 as enhancer regulatory regions, and HOXA-AS2, MIR219-2, and RP11-834C11.3 as dyadic regulatory regions of these ncRNAs. In addition, two miRNAs, termed MIR199A2 and MIR152, were found to have high enrichment of osteogenic-related terms. Upon further examination of the role of MIR152 on osteoblast differentiation, we found that MIR152 knockdown induced upregulation of ALP and COL1A1 in Saos-2 cells. Thus, ncRNAs were found to regulate the osteogenic differentiation potentials of hiPSCs that are used for bone regeneration and repair owing to their differentiation potentials. These data allow understanding ncRNA profiles of hiPSCs during osteogenesis.

Study JGAS000248

LCLF1.0 Data

In this study, we investigated ad libitum food intake of 20 healthy adult volunteers who each completed a 4-week stay at the National Institutes of Health (NIH). During their stay, they consumed a low-carbohydrate, high-fat (LCHF) diet and a low-fat, high-carbohydrate (LFHC) diet for 2 weeks each, in random order. We collected information about energy intake and metabolic changes in response to the two test diets. The test diets were presented to subjects in amounts exceeding their daily energy requirements, and subjects were instructed to eat as much or as little of each diet as desired. This study implemented 7-day rotating menus for each test diet. The diets were matched for presented calories and protein, but the LCHF diet was low in carbohydrate (~10% of calories) and high in fat (~75% of calories) whereas the LFHC diet was high in carbohydrates (~75% of calories) and low in fat (~10% of calories). The two test diets had a common foundation of vegetables with low amounts of digestible carbohydrates such as lettuce, spinach, kale, cabbage, cauliflower, zucchini, tomato, asparagus, broccoli, peppers, brussels sprouts, and green beans. The LCHF diet included meat, poultry, fish, eggs, dairy, and nuts. The LFHC diet included legumes, rice, root vegetables, soy products, corn, lentils, peas, whole grains, bread, and fruit. The test diets were designed using a standard computerized nutrition database, and blood samples were collected from the subjects.

Study phs003187

Identification of RNA biomarkers in Parkinson's disease patients

Parkinson?s disease (PD) is an age-related, chronic and progressive neurodegenerative disorder characterized by a loss of dopaminergic neurons and subsequent motor symptoms. These overt motor symptoms are often preceded by prodromal non-motor symptoms. Though a number of genetic and environmental factors have been identified to play a role in PD, more exact methods for both diagnosing and assessing prognosis are yet to be discovered. By analyzing the transcriptome of early-stage PD patients, this study aims to identify genes (including important non-coding RNAs) and pathways altered at disease onset that may be used as novel biomarkers for PD diagnosis as well as potential new drug targets. The study consists of three main sources of data: first year blood transcriptomes, second year blood transcriptome and matched neural stem cell (NSC)/neuron transcriptomes. All transcriptome libraries were synthesized and sequenced using no-amplification non-tagging cap analysis of gene expression (nAnT-iCAGE) on the Illumina HiSeq 2500 platform. Resulting data was mapped to the human genome annotation (hg38), processed CAGE tags were clustered ready for differential expression analyses. First year blood sequencing consisted of 22 PD patients and 10 healthy controls across four lanes. In the second year, a further four lanes were sequenced containing 17 PD patients (12 patients from the first year and 5 new patients) along with 10 healthy controls and 5 first year blood samples matching the new second year patients.

Study JGAS000119

Centers for Common Disease Genomics (CCDG) - Whole Genome Sequencing in Type 1 Diabetes (T1DGC)

The Type 1 Diabetes Genetics Consortium (T1DGC) was established to collect resources (biological samples and data) and conduct research to better understand the genetic basis of type 1 diabetes (T1D). Collection was initiated by ascertaining affected sib-pair families (both parents, two affected siblings and, when available, an unaffected sibling), collected from five geographic regions through four recruitment networks (Asia-Pacific, Europe, North America, United Kingdom). In addition, the T1DGC collected trio families (both parents and affected child) and cases and controls from low-prevalence populations (African-American, with four grandparents self-reporting as African ancestry; Mexican-American, with four grandparents self-reporting as ancestry from Mexico). The T1DGC also served as a repository for contributed collections from other studies, all meeting the broad data-sharing policy of the T1DGC, for inclusion in the genetic studies. These collections include T1D case samples ascertained from the UK Genetic Resource Investigating Diabetes (UK GRID) cohort, SEARCH for Diabetes in Youth (SEARCH), The Genetics of Kidneys in Diabetes (GoKinD), and control samples obtained from the British 1958 Birth Cohort, the UK National Blood Services collection, CLEAR (Consortium for the Longitudinal Evaluation of African-Americans with Early Rheumatoid Arthritis), the New York Cancer Project (NYCP), and other cohorts. For the NHGRI-funded Centers for Common Disease Genomics (CCDG) project, participants with T1D and ancestry-matched controls were identified through the T1DGC, either through direct ascertainment or by contribution from other sources to the T1DGC. As the CCDG has focused initially on non-Caucasian populations for whole genome sequencing, T1DGC participants of African, Mexican and Asian ancestry (targeting ~1200 cases and ~1200 controls in each ancestral group) and a small group of participants of Northern European ancestry (~100 cases, ~100 controls) were to be contributed to the study. Whole genome sequencing of T1DGC samples would be conducted at Washington University McDonnell Genome Institute and based upon matching case-control status within an ancestry group and prioritization by the CCDG.

Study phs001222

Research of factors related to diagnosis, progression, prognosis and treatment of hepato-biliary-pancreatic malignancies

Advanced cancers with metastasis and/or recurrence are usually resistant and refractory to treatment. In our studies, whole exome sequencing analysis, comprehensive epigenetic analysis and genome-wide expression analysis were performed using cancerous and non-cancerous tissues derived from multicentric cohort study of hepatocellular carcinoma (HCC). The aim of the studies is identification of the refractoriness-related deriver genes for application to novel molecular targeted therapy and preventive medicine. The studies are intended for refractory HCC. High frequency of the tumor recurrence even after curative resection is one of the major difficulties in the treatment of HCC. According to our previous studies, not the recurrence itself, but the recurrence pattern has critical effects on prognosis of the patient with HCC. Then, we analyzed the cancerous and non-cancerous tissues of primary HCC on the point of the recurrence patterns in accordance with or without Milan criteria. The materials were obtained from thirty three patients underwent curative hepatectomy for HCC at Department of Hepato-Biliary-Pancreatic Surgery, Tokyo Medical and Dental University Hospital. Written informed consent from these patients, as well as the institutional review board approved was obtained. The determination of the refractory HCC group (16 cases) was based on the point of the recurrence patterns in accordance with Milan criteria for the recurrent tumor (solitary <5cm, or up to 3 nodules <3 cm, without major vascular invasion or distant metastasis) that has been proposed as the useful criteria of the liver transplantation for HCC. The cellular DNA was extracted from the cancerous and non-cancerous tissues of primary HCC by the phenol-chloroform method. After SNP certification using Genome-Wide Human SNP Array 6.0 (Affymetrix), whole exome sequencing was performed at the Cancer Institute of JFCR, as the support infrastructure. Exome sequencing was performed using HiSeq 2000 (Illumina), and the obtained reads were mapped to the human reference genome (hg19) using BWA software. GATK software was used for local realignment base call recalibration. Single nucleotide variants (SNVs) and indels were analyzed by MuTect and SomaticIndelDetector, as well as visual confirmation by IGV software.

Study JGAS000052

Therapeutic Resistance to PI3K-alpha Inhibitors

We have studied the tumor genomic evolution in a patient with metastatic breast cancer bearing an activating PIK3CA mutation. The patient was treated with the PI3Kα inhibitor BYL719 and achieved a lasting clinical response on BYL719, but eventually progressed to treatment and died shortly thereafter. A rapid autopsy was performed and a total of 14 metastatic lesions were collected for further analysis. In order to identify possible genetic determinants of acquired resistance to PI3Kα inhibition, we took a three-step approach. First, we examined both the primary tumor (before BYL719 treatment) and the new lung metastasis by whole genome sequencing (DNA from the spleen was used as a normal control). Then, we analyzed the primary tumor, lung metastasis, and the peri-aortic lesion that remained stable (responding) at the time of progression to BYL719 therapy by whole exome sequencing. Finally, to confirm and expand our findings, we sequenced the primary tumor and all the metastatic lesions to >500-fold coverage using a custom targeted deep-sequencing assay, MSK-IMPACT. Using this 3-step approach, we have demonstrated that patient’s lesion underwent parallel genetic evolution at multiple metastatic sites with different PTEN genomic alterations leading to a convergent PTEN- null phenotype resistant to PI3Kα inhibition. In order to expand our observations, we analyzed paired samples (pre-treatment and at progression) from six additional patients enrolled in the BYL719 trial. Acquired bi-allelic loss of PTEN was found in one additional patient treated with BYL719 whereas in two patients PIK3CA mutations present in the primary tumor were no longer detected at the time of progression. To functionally characterize our findings, inducible PTEN knockdown in sensitive cells resulted in resistance to BYL719, while simultaneous PI3K-p110β blockade reverted this resistance phenotype, both in cell lines and in PTEN-null xenografts derived from our patient. We conclude that parallel genetic evolution of separate sites with different PTEN genomic alterations leads to a convergent PTEN-null phenotype resistant to PI3Kα inhibition.

Study EGAS00001000991

APOBEC mutagenesis is a common process in normal human small intestine

The single base substitution mutational signatures SBS2 and SBS13, likely caused by APOBEC cytosine deaminases, are common in many human cancer types. However, the stimulus activating APOBEC mutagenesis is unknown and understanding of when it occurs in the progression from normal to cancer cell is limited. Here, as part of a wider survey of human tissues, we whole genome sequenced 342 microdissected normal epithelial crypts from the small intestines of 39 individuals. SBS2/13 mutations were present in 17% normal small intestine crypts and were likely due to APOBEC3A activity. Localised clusters of SBS2/13 mutations (kataegis) were also commonly found. APOBEC mutation burdens were variable between individuals and between crypts from the same individual. Crypts with SBS2/13 often had immediate crypt neighbours without SBS2/13, suggesting that the underlying cause of SBS2/13 is cell-intrinsic rather than a widely distributed microenvironmental exposure, or needs to be permitted by cell-intrinsic conditions. APOBEC mutagenesis occurred throughout the human lifespan, including in young children, and was episodic with a small number of episodes occurring during the life history of a single cell. The results indicate that APOBEC mutagenesis is more common in the small intestine epithelium than in many other cell types, and is an episodic process in vivo initiated or permitted by cell intrinsic factors.

Dataset EGAD00001008764

Genetic Determinants of EGFR-Driven Lung Cancer Growth and Therapeutic Response In Vivo

Oncogenic alterations in EGFR frequently co-occur with additional genetic alterations in EGFR-driven lung adenocarcinoma (LUAD), but how specific combinations of mutations affect tumor phenotypes and responses to targeted therapy is yet unknown. We leveraged a genetically engineered mouse model of EGFR mutant/Trp53-deficient LUAD to study the consequences of inactivating 10 different tumor suppressor genes on the fitness and tyorosine kinase inhibitor (TKI) sensitivity of these tumors. We found that loss of Keap1 is associated with a reduced response to therapy. In patients, we found that mutations in the KEAP1/NFE2L2/CUL3 pathway are associated with a significantly shorter time to treatment failure for EGFR TKI therapy compared to matched patients with wild-type KEAP1/NFE2L2/CUL3 tumors. We also analyzed whole exome sequencing data from tumor specimens before TKI treatment and at the time of treatment resistance for mutations in the KEAP1 pathway and these data are being submitted here.  

Study phs002334

Spatial Transcriptomics Reveals Discrete Tumor Microenvironments and Autocrine Loops Within Ovarian Cancer Subclones

Ovarian masses from patients with high grade serous ovarian carcinoma undergoing debulking surgery were subjected to spatial transcriptomics profiling using the 10x Genomics Visium (fresh frozen) platform. Copy number inference using inferCNV predicted the presence of subclones with mutually exclusive copy number alterations (CNAs) in 5 of the 8 patient samples studied. In one patient, 3 subclones were predicted. For this patient sample, a serial section of the same tumor was used to microdissect regions corresponding to each of these subclones, and a 'normal' region predicted to contain only fibroblasts and no tumor cells. These microdissected regions were processed for low pass whole genome sequencing (WGS) and CNAs recorded using ichorCNA. An oral biopsy lacking tumor cells from an unrelated donor was used as a negative control for CNA inference. The CNAs predicted by inferCNV for the three subclones were validated by the low pass WGS and no CNAs were observed in the normal region containing fibroblasts.

Study phs003561

11745 results for "cancer rna-seq"

in 23.01 milliseconds.