Search Results - EGA European Genome-Phenome Archive

Spatial and temporal evolution of distal 10q deletion, a prognostically unfavorable event in diffuse low-grade gliomas

Background: The disease course of patients with diffuse low-grade glioma is notoriously unpredictable. Temporal and spatially distinct samples may provide insight into the evolution of clinically relevant copy number aberrations (CNAs). The purpose of this study is to identify CNAs that are indicative of aggressive tumor behaviour and can thereby complement the prognostically favorable 1p/19q co-deletion. Results: Genome-wide, 50 base pair single-end, sequencing was performed to detect CNAs in a clinically well-characterized cohort of 98 formalin-fixed paraffin-embedded low-grade gliomas. CNAs are correlated with overall survival as an endpoint. Seventy-five additional samples from spatially distinct regions and paired recurrent tumors of the discovery cohort were analysed to interrogate the intratumoral heterogeneity and spatial evolution. Loss of 10q25.2-qter is a frequent subclonal event and significantly correlates with an unfavorable prognosis. A significant correlation is furthermore observed in a validation set of 126 and confirmation set of 184 patients. Loss of 10q25.2-qter arises in a longitudinal manner in paired recurrent tumor specimens, whereas the prognostically favorable 1p/ 19q co-deletion is the only CNA that is stable across spatial regions and recurrent tumors. Conclusions: CNAs in low-grade gliomas display extensive intratumoral heterogeneity. Distal loss of 10q is a late onset event and a marker for reduced overall survival in low-grade glioma patients. Intratumoral heterogeneity and higher frequencies of distal 10q loss in recurrences suggest this event is involved in outgrowth to the recurrent tumor.

Dataset EGAD00001001000

RNA-seq data from 164 advanced prostate tumors generated by the West Coast Dream Team including 42 paired samles

164 pairs of FASTQ files from metastatic Castration-Resistant Prostate Cancer (mCRPC) sequenced on HiSeq 4000 instruments. Patients were enrolled in the West Coast Dream Team study. Biopsies include various tissue sites including bone, soft tissue, and lymph node. 42 pairs prior to enzalutamide treatment and at progression from 21 patients are included.

Dataset EGAD00001009065

Evolutionary Origins of Recurrent Pancreatic Cancer

Surgery is the only curative option for patients with Stage I/II pancreatic cancer, nonetheless most patients will recur after surgery and die of their disease. To identify novel opportunities for management of recurrent pancreatic cancer we performed whole exome or targeted sequencing of 10 resected primary cancers and their matched intrapancreatic recurrences or distant metastases. We identified that recurrent disease develops from a monophyletic or polyphyletic origin, and this distinction has potential clinical relevance. In all patients, treatment induced genetic bottlenecks led to a modified genetic landscape and subclonal heterogeneity for driver gene alterations in part due to intermetastatic seeding. In one patient what was believed to be recurrent disease was an independent (second) primary tumor. These findings strongly advocate for routine post-treatment sampling in the management of recurrent pancreatic cancer.

Study EGAS00001004097

Tumor-associated preferred end coordinates and somatic variants as signatures of circulating tumor DNA

Cell-free DNA fragmentation is a nonrandom process. We showed that cell-free DNA fragments with ends at certain genomic coordinates had higher likelihoods of being derived from hepatocellular carcinoma. Other coordinates were associated with cell-free DNA molecules originating from the liver. Quantitative assessment of cell-free DNA molecules bearing these respective groups of end signatures correlated with the amounts of tumor-derived or liver-derived DNA in plasma. There were millions of tumor-associated plasma DNA end coordinates across the genome. Due to their high prevalence, they were more readily detectable than somatic mutations as a cancer signature in plasma. Hence, detection of tumor-associated plasma DNA ends may offer a cost-effective means of capturing evidence for the presence of cancer through liquid biopsy assessment.

Study EGAS00001003160

UAMS Smoldering Myeloma Timeline Cohort

To better understand the pattern of genetic changes over time, we performed whole exome sequencing of sequential bone marrow samples from 9 patients taken overtime including some paired SMM/newly diagnosed MM/Relapse MM samples. Samples from 9 patients (9 controls and 53 tumors) underwent whole exome sequencing with an additional capture for the IGH, IHK, IGL, and MYC loci. DNA was obtained from either CD138+ cells from the bone marrow of smoldering myeloma patients through time (tumor) or from stem cell harvests or peripheral blood cells from the same patient (control). 100 ng of DNA was fragmented, end-repaired, and adapters ligated using NimbleGen's MedExome. After PCR amplification hybridized libraries underwent further amplification before being sequenced on a NextSeq500 (Illumina) using 75 bp paired end reads.

Study EGAS00001003687

Exome sequence data for germline, primary tumor, and relapse tumor of a transformed non-Hodgkins lymphoma patient with unexpected long-time remission

The patient was diagnosed with a transformed high-grade non-Hodgkin lymphoma stage III, and treated with conventional R-CHOP (Rituximab (R), Cyclophosphamide (C), Doxorubicin (H), Vincristine (O) and Prednisone (P)). Unfortunately, she suffered from severe toxicity but recovered during the following six months remission until a biopsy verified relapse. The patient refused second line combination chemotherapy, but accepted a 3 months palliation with R and Chlorambucil. Unexpectedly, she obtained continuous complete remission and is at present >9 years after primary diagnosis.Molecular studies and data evaluation by principal component analysis, mutation screening, and copy number variations of the primary and relapsed tumor, identified patterns of branched lymphoma evolution, most likely diverging from an unknown in situ follicular lymphoma.

Study EGAS00001001973

UCSF Pediatric Bithalamic Glioma Genome Project

Brain tumors are the most common solid tumors of childhood, and the genetic drivers and optimal therapeutic strategies for many of the different subtypes remain unknown. We performed targeted next-generation sequencing of approximately 500 cancer-associated genes on a cohort of 13 pediatric bithalamic diffuse gliomas, a lethal brain tumor of childhood for which the genetic basis is largely unknown. We identified that bithalamic diffuse gliomas harbor frequent mutations in the EGFR oncogene in the absence of accompanying gene amplification and only rare histone H3 mutation. These EGFR mutations were either small in-frame insertions within exon 20 (intracellular tyrosine kinase domain) or missense mutations within exon 7 (extracellular ligand-binding domain). Accompanying alterations included frequent TP53 mutation, CDK6 amplification or CDKN2C mutation, and BCOR and BCORL1 mutation or deletion.

Study EGAS00001004033

Non-Mendalian inheritance of extrachromosal DNA elements can drive disease evolution in glioblastoma

Genomic heterogeneity of glioblastoma (GBM) is suspected to contribute to the poor response to therapy of this disease. We compared molecular characteristics between primary GBM, neurospheres and orthotopic xenograft models derived from the same parental tumor. Driver alterations were in majority propagated from tumor to model systems. Extrachromosomal amplifications of MET, a proto-oncogene coding for a receptor tyrosine kinase, were detected in three primary GBM, largely discarded in neurospheres cultures, but resurfaced in xenografts. The clonal dynamics inferred by somatic single nucleotide variants (sSNVs) in MET-amplified samples diverged from the pattern delineated by the MET amplification event suggesting that the MET event and sSNVs were inherited in different manners. Our analysis shows that extrachromosomal elements are able to drive tumor progression.

Study EGAS00001001878

MYC Drives Progression of Small Cell Lung Cancer to a Variant Neuroendocrine Subtype with Vulnerability to Aurora Kinase Inhibition

Loss of the tumor suppressors RB1 and TP53 and MYC amplification are frequent oncogenic events in small cell lung cancer (SCLC). We show that Myc expression cooperates with Rb1 and Trp53 loss in the mouse lung to promote aggressive, highly metastatic tumors, that are initially sensitive to chemotherapy followed by relapse, similar to human SCLC. Importantly, MYC drives a neuroendocrine-low “variant” subset of SCLC with high NEUROD1 expression corresponding to transcriptional profiles of human SCLC. Targeted drug screening reveals that SCLC with high MYC expression is vulnerable to Aurora kinase inhibition, which combined with chemotherapy strongly suppresses tumor progression and increases survival. These data identify molecular features for patient stratification and uncover a novel targeted treatment approach for MYC-driven SCLC.

Study EGAS00001002115

Genetic landscape of malignant peripheral nerve sheath tumors

Neurofibromatosis 1 is a hereditary syndrome characterized by the development of numerous benign neurofibromas, a small subset of which progress to malignant peripheral nerve sheath tumors (MPNSTs). To better understand the genetic basis for MPNSTs, we performed whole genome sequencing on four MPNSTs from patients with neurofibromatosis 1 and found that each of them had a somatic, inactivating mutation of SUZ12, a chromatin modifying gene adjacent to the NF1 gene responsible for the benign neurofibromas in these patients. We then performed targeted sequencing on an additional 46 MPNSTs and found that 12 had somatic mutations in SUZ12. Fifteen of the 17 (88%) mutations in SUZ12 were predicted to inactivate protein function, implicating it as a tumor suppressor gene possibly responsible for the progression from neurofibromas to MPNTs.

Study EGAS00001000974

Whole-genome sequencing of bladder cancers of various stages and grades to search for driver mutations, chromosome-scale somatic changes, mutation signatures and clonal structures.

This discovery set of tumours cancers with whole-genome sequence data comprised 14 bladder cancers, paired with peripheral blood, that had been collected from unrelated individuals presenting to the Urology Department, Royal Hallamshire Hospital, Sheffield between June 2008 and September 2011. Four cancers were of low-grade papillary morphology (pTaG1-2), five were high grade invading the lamina propria (pT1G3, with two subsequently becoming muscle-invasive); and five were muscle-invasive (pT2-pT3). All tumours were sampled at transurethral resection or cystectomy and had not previously received any other therapy. The presence of a majority of cancer cells in the tumour specimens was confirmed by routine histological assessment. Genomic DNA was extracted from each tumour and paired blood sample using standard methods.

Study EGAS00001000738

Cross-species genomics identifies TAF12, NFYC and RAD54L as novel choroid plexus carcinoma oncogenes

Choroid plexus carcinomas (CPC) are poorly understood and frequently lethal brain tumors with minimal treatment options. Using a new mouse model of the disease and a large cohort of human CPCs, we performed a cross-species, genome-wide search for novel oncogenes within syntenic regions of chromosome gain. TAF12, NFYC and RAD54L, co-located on human chromosome 1p32-35.3 and mouse chromosome 4qD1-D3, were identified as oncogenes that are gained in tumors in both species and required to initiate and progress the disease in mice. TAF12 and NFYC are transcription factors that regulate the epigenome, while RAD54L plays a central role in DNA repair. Our data identify a group of concurrently gained, novel oncogenes that cooperate in the formation of CPC and unmask potential new avenues for therapy.

Study EGAS00001000961

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

Pediatric Low-Grade Glioma RNA and Targeted Sequencing

Pediatric low-grade gliomas (pLGG) are frequently driven by genetic alterations in the RAS/MAPK pathway yet show unexplained variability in their clinical outcome. To address this, we characterized a cohort of >1,000 clinically annotated pLGG. 84% of cases harbored a driver alteration, while those without an identified alteration also often exhibited up-regulation of the RAS/MAPK pathway. pLGG could be broadly classified based on their alteration type. Rearrangement-driven tumors were diagnosed at a younger age, enriched for WHO grade I histology, infrequently progressed, and rarely resulted in death as compared to SNV-driven tumors. Further sub-classification of clinical-molecular correlates stratified pLGG into risk categories. These data highlight the biological and clinical differences between pLGG subtypes and opens avenues for future treatment refinement.

Study EGAS00001004242

Recurrent Somatic Mutations of PTPN1 in Primary Mediastinal B cell lymphoma and Hodgkin Lymphoma

Hodgkin lymphoma (HL) and primary mediastinal B cell lymphoma (PMBCL) are related lymphomas sharing pathological, molecular and clinical characteristics. Here, we discovered recurrent somatic coding sequence mutations of the tyrosine phosphatase gene PTPN1 in the tumor genomes and transcriptomes of these B cell lymphomas (6 of 30 or in 20% of HL cases and 13 of 49 or in 27% of PMBCL cases), consisting of nonsense, missense and frameshift mutations. We demonstrate that PTPN1 mutations lead to reduced phosphatase activity and increased phosphorylation of JAK-STAT pathway members. Moreover, silencing of PTPN1 by RNA interference in HL cell line KM-H2 resulted in hyperphosphorylation and overexpression of downstream oncogenic targets. Our data establish PTPN1 mutations as novel drivers in B cell lymphomagenesis.

Study EGAS00001000554

Most HCCs in Taiwan show the mutational signature of aristolochic acid

Plants in the genus Aristolochia contain the mutagen aristolochic acid (AA) and have been widely used in traditional medicines and for weight loss. AA binds covalently to genomic DNA and induces a highly distinctive mutational signature. While AA involvement in urinary-tract cancers in Taiwan is known, the possible role of AA in hepatocellular carcinomas (HCCs) in Taiwan has not been examined. Here, we whole-exome sequenced 98 unselected HCCs from Taiwan and analyzed the mutational signatures for evidence of AA mutagenesis. Remarkably, more than 78% of HCCs showed strong evidence of AA mutagenesis, often associated with high mutation burdens. Non-synonymous mutations in genes known to be HCC driver genes were detected. Importantly, we elucidated the potential of immunotherapy in this cohort of liver cancer patients.

Study EGAS00001002301

A genetic compendium of human brains from the UK Medical Research Council brain tissue resource

Common neurodegenerative diseases have a complex genetic architecture. Highly penetrant diseases alleles are found in a significant minority of cases, and common risk alleles are present in a large proportion. Given the central role of genetic factors in the pathogenesis of these disorders, it is critical that mechanistic studies in human subjects and tissue samples are interpreted in an genetically enlightened context. To address this we performed exome sequencing on 1461 human brains accessible through the Medical Research Council (UK) brain banks network. Our findings confirm the complex genetic landscape of neurodegenerative disease. Clinical, pathological and genetic data for the 1461 brains with corresponding exome sequencing data are available within this dataset, enabling the genetic stratification and selection of post-mortem tissue samples for researchers.

Study EGAS00001001599

Whole exome sequencing in RVOT patients

In a patient with right ventricular outflow tract (RVOT) tachycardia we identified a heterozygous point mutation in the selectivity filter of the stretch-activated K2P potassium channel TREK-1 (KCNK2 or K2P2.1). This mutation introduces abnormal sodium permeability to TREK-1 In addition, mutant channels exhibit a hypersensitivity to stretch-activation, suggesting that the selectivity filter is directly involved in stretch-induced activation and desensitization. Increased sodium permeability and stretch-sensitivity of mutant TREK-1 channels may trigger arrhythmias in areas of the heart with high physical strain such as the RVOT. We present a pharmacological strategy to rescue the selectivity defect of the TREK-1 pore. Our findings provide important insights for future studies of K2P channel stretch-activation and the role of TREK-1 in mechano-electrical feedback in the heart.

Study EGAS00001002319

ICGC Oesophageal adenocarcinoma - tumour samples

The oesophageal project will focus on adenocarcinoma which is increasing in incidence in the UK and other developed countries and has a very poor outcome. The primary aims of this project are to deeply sequence tumour and normal genomic DNA (including the precursor condition Barrett’s oesophagus when material is available) to provide a comprehensive catalogue of somatic mutations. This will be achieved through a UK-wide network of hospitals involved in a research collaboration called the OCCAMS consortium. The goal of this project is to use high quality clinical material with accurately annotated clinic-pathological, treatment and outcome data.

Study EGAS00001000725

Two lung cancer cell lines with EGFR mutations, PC-9 and KHM-3S, were either treated with Tarceva for 24 hours or left untreated. The gene expression profiles were examined by RNAseq, and the genome wide binding profiles of total STAT3 and pSTAT3 were characterized by ChIPseq.

Lung cancers harboring activating EGFR mutants show dramatic responses to EGFR TKIs, such as Tarceva. However, nearly all patients show relapse within 1 year after initial treatment. To investigate the early signaling switches that are involved in the formation of drug resistance, and the role of STAT3 in the early signaling switches involved in the formation of drug resistance, we have treated two lung cancer cell lines with EGFR mutations, PC-9 and KMH-3S, with Tarceva for 24hours. The RNA samples with and without treatment were collected in triplicate for RNAseq experiment.The total STAT3 and pSTAT3 chromatinIP were done on samples with and without treatment for ChIPseq.

Study EGAS00001000793

Spatio-temporal evolution of the primary glioblastoma genome

Tumor recurrence following treatment is the major cause of mortality for glioblastoma multiforme (GBM) patients. Thus, insights on the evolutionary process at recurrence are critical for improved patient care. Here, we describe our genomic analyses of 38 GBM patients with the initial and recurrent tumor specimens for each individual. A substantial divergence in the landscape of driver alterations was associated with distant appearance of a recurrent tumor from the initial tumor, suggesting that the genomic profile of the initial tumor can mislead targeted therapies for the distally recurred tumor. In addition, in contrast to IDH1-mutated gliomas, IDH1-wild-type primary GBMs rarely developed hypermutation following temozolomide (TMZ) treatment, indicating low risk of TMZ-induced hypermutation for these patients under the standard regimen.

Study EGAS00001001041

Multisample genomic analysis of solid childhood cancers using high resolution SNP-arrays, Whole Exome Sequencing and Targeted Deep Sequencing.

We mapped the prevalence of genetically distinct clones over 248 regions in 54 childhood cancers. This revealed that primary tumors can simultaneously follow up to four evolutionary patterns in different anatomic areas. The most common pattern consists of a fluctuating presence over anatomic space of subclones with very few mutations. The second most common is a surprisingly stable coexistence, over vast areas, of clones with different changes in chromosome numbers. This is contrasted by a third, less frequent, pattern where a novel clone harboring driver mutations or structural chromosome rearrangements completely replaces its progenitor. The fourth and rarest pattern is the local emergence of a myriad of clones with TP53 inactivation. Strikingly, death from disease was limited to tumors exhibiting the two latter, most dynamic patterns.

Study EGAS00001002662

ICGC PedBrain: Deep-sequencing of childhood brain tumors.

Brain tumors constitute the childhood tumors with the highest mortality rates and survival is often associated with severe long-term sequelae due to intensive multimodal treatment regimens. Thus, the PedBrainTumor network aims at the identification of robust biomarkers for clinical management and novel molecular targets for therapeutic interventions. Using massively parallel whole-genome sequencing, and transcriptome and methylome sequencing for subsets of cases, we aim to decipher the molecular causes of medulloblastoma as well as low-grade astrocytoma, and to identify markers to stratify patients for specialized treatment. As the PedBrain network is affiliated with clinical trials in medulloblastoma and pilocytic astrocytoma, validation cohorts for the translation of key findings into clinical settings are readily available.

Study EGAS00001000215

Size-tagged preferred ends in maternal plasma DNAshed light on the production mechanism and showutility in noninvasive prenatal testing

Cell-free DNA molecules in the plasma of pregnant women exhibit nonrandom fragmentation with preferred end sites. We studied if such preferred end sites might bear any re- lationship with fragment lengths of plasma DNA. Short and long plasma DNA molecules were associated with different preferred DNA end sites. Analysis of size-tagged preferred ends could be used for measuring fetal DNA fraction and for facilitating fetal trisomy 21 detection. Fetal preferred end sites were generally located in the nucleosome cores, while the maternal ones were located in the linker regions. This con- ceptual framework provides an explanation of the relative shortness of fetal DNA in maternal plasma and brings us closer to understanding the biological mechanisms that influence plasma DNA fragmentation.

Study EGAS00001002831

RNA-seq of Glioblastoma stem cells

Chromatin accessibility discriminates stem from mature cell populations, enabling the identification of primitive stem-like cells in primary tumors, such as Glioblastoma (GBM) where self-renewing cells driving cancer progression and recurrence are prime targets for therapeutic intervention. We show, using single-cell chromatin accessibility, that primary GBMs harbor a heterogeneous self-renewing population whose diversity is captured in patient-derived glioblastoma stem cells (GSCs). In depth characterization of chromatin accessibility in GSCs identifies three GSC states: Reactive, Constructive, and Invasive, each governed by uniquely essential transcription factors and present within GBMs in varying proportions. Orthotopic xenografts reveal that GSC states associate with survival, and identify an invasive GSC signature predictive of low patient survival. Our chromatin-driven characterization of GSC states improves prognostic precision and identifies dependencies to guide combination therapies.

Study EGAS00001003070

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