3311 results for "*geneti*"

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• Divergence between high metastatic tumor burden and low circulating tumor DNA concentration in metastasized breast cancer

  Circulating tumor DNA (ctDNA) was reported to represent a highly sensitive biomarker of metastatic cancer disease directly reflecting tumor burden and dynamics. Here we investigated the role of ctDNA in patients with metastatic breast cancer. In an index patient with more than 100,000 circulating tumor cells (CTCs) in serial blood analyses, whole genome, exome, or targeted deep sequencing of the primary tumor, metastases, and 551 CTCs were consistent with a genetically homogeneous cancer. However, the allele fractions (AFs) of ctDNA were only 2-3% in each analysis, which did neither reflect the tumor burden nor the dynamics of this progressive disease by far. Indeed, plasma analyses of 71 further patients demonstrated highly variable AFs of mutant fragments, which frequently did not correspond to the tumor burden. These results provide insights into mechanisms involved in CTC and ctDNA release into the circulation and have important implications for diagnostic tests based on liquid biopsies.

  Study EGAS00001000625

• Genome of the Netherlands

  The Genome of the Netherlands (GoNL) Project characterizes DNA sequence variation, common and rare, for SNVs, short insertions and deletions (indels) and larger deletions in 769 individuals of Dutch ancestry selected from five biobanks under the auspices of the Dutch hub of the Biobanking and Biomolecular Research Infrastructure (BBMRI-NL). The samples come from a representative sample of 250 trio-families from all provinces in the Netherlands. The parent-offspring trios include adult individuals ranging in age from 19 to 87 years (mean=53 years; SD=16 years) from birth cohorts 1910-1994. Sequencing was done on blood-derived DNA from uncultured cells and accomplished coverage was 14-15x. Samples where contributed by LifeLines (http://lifelines.nl/lifelines-research/general), The Leiden Longevity Study (http://www.healthy-ageing.nl; http://www.langleven.net), The Netherlands Twin Registry (NTR: http://www.tweelingenregister. org), The Rotterdam studies, (http://www.erasmus-epidemiology.nl/rotterdamstudy) and the Genetic Research in Isolated Populations program (http://www.epib.nl/research/geneticepi/research.html#gip). The sequencing was carried out in collaboration with the Beijing Institute for Genomics (BGI). The analysis was done by a consortium lead by UMCG, LUMC, Erasmus MC, VU university and UMCU, see http://www.nlgenome.nl. Funding for the project was provided by the Netherlands Organization for Scientific Research under award number 184021007, dated July 9, 2009 and made available as a Rainbow Project of the Biobanking and Biomolecular Research Infrastructure Netherlands (BBMRI-NL).

  Study EGAS00001000644

• A Genomics-Based Classification of Human Lung Tumors

  We characterized genome alterations in 1255 clinically annotated lung tumors of all histological subgroups to identify genetically defined and clinically relevant subtypes. More than 55% of all cases had at least one oncogenic genome alteration potentially amenable to specific therapeutic intervention, including several personalized treatment approaches that are already in clinical evaluation. Marked differences in the pattern of genomic alterations existed between and within histological subtypes, thus challenging the original histomorphological diagnosis. Immunohistochemical studies confirmed many of these reassigned subtypes. The reassignment eliminated almost all cases of large cell carcinomas, some of which had therapeutically relevant alterations. Prospective testing of our genomics-based diagnostic algorithm in 5145 lung cancer patients enabled a genome-based diagnosis in 3863 (75%) patients, confirmed the feasibility of rational reassignments of large cell lung cancer, and led to improvement in overall survival in patients with EGFR-mutant or ALK-rearranged cancers. Thus, our findings provide support for broad implementation of genome-based diagnosis of lung cancer.

  Study EGAS00001000647

• Microsatellite data show recent demographic expansions in sedentary but not in nomadic human populations in Africa and Eurasia.

  The transition from hunting and gathering to plant and animal domestication was one of the most important cultural and technological revolutions in human history. According to archeologists and paleoanthropologists, this transition triggered major demographic expansions. However, few genetic studies have found traces of Neolithic expansions in the current repartition of genetic polymorphism, pointing rather toward Paleolithic expansions. Here, we used microsatellite autosomal data to investigate the past demographic history of 87 African and Eurasian human populations with contrasted lifestyles (nomadic hunter-gatherers, semi-nomadic herders and sedentary farmers). Likely due to the combination of a higher mutation rate and the possibility to analyze several loci as independent replicates of the coalescent process, the analysis of microsatellite data allowed us to infer more recent expansions than previous genetic studies, potentially resulting from the Neolithic transition. Despite the variability in their location and environment, we found consistent expansions for all sedentary farmers, while we inferred constant population sizes for all hunter-gatherers and most herders, which could result from constraints linked to a nomadic or semi-nomadic lifestyle and/or competition for land between herders and farmers. As an exception, we inferred expansions for Central Asian herders. This might be linked with the arid environment of this area, which may have been more favorable to nomadic herders than to sedentary farmers. Alternatively, current Central Asian herders may descent from populations who have first experienced a transition from hunter-gathering to sedentary agropastoralism, and then a second transition to nomadic herding.

  Study EGAS00001000652

• Biallelic DICER1 mutations in sporadic pleuropulmonary blastoma

  Pleuropulmonary blastoma (PPB) is an extremely rare pediatric malignancy in the lung, whose pathogenesis is poorly understood, except for recent reports of frequent germline heterozygous DICER1 mutations. To investigate the genetic basis of PPB, we performed whole-exome sequencing in 7 representative PPB cases, followed by targeted deep sequencing in 12 cases with PPB. DICER1 mutations were found in 11/12 cases. Biallelic DICER1 mutations were common in PPB, in which RNase IIIb domain mutations were found in all cases with or without nonsense/frameshift mutations and were somatic in all evaluable cases. A majority of cases had mutated DICER1 alleles in germline with or without an additional somatic mutation in the remaining allele, while other cases had exclusively somatic mutations involving the RNase IIIb domain. TP53 deletions/mutations were detected in 8/12 cases. Our results highlight a unique role of the RNase IIIb domain mutations and TP53 inactivation in PPB pathogenesis.

  Study EGAS00001000662

• Integrated genomic characterization of adrenocortical carcinoma

  Adrenocortical carcinomas (ACC) are aggressive cancers originating in the cortex of the adrenal glands. Despite the overall poor prognosis, ACC outcome is heterogeneous. CTNNB1 and TP53 mutations are frequent in these tumors, but the complete spectrum of genetic changes remains undefined. Exome sequencing and SNP array analysis of 45 ACC revealed recurrent alterations in known drivers (CTNNB1, TP53, CDKN2A, RB1, MEN1) and genes not previously reported to be altered in ACC (ZNRF3, DAXX, TERT and MED12), which were validated in an independent cohort of 77 ACC. The cell-surface transmembrane E3 ubiquitin ligase ZNRF36 was the gene the most frequently altered (21%), and appears as a potential novel tumor suppressor gene related to the ß-catenin pathway. Our integrated genomic analyses led to the identification of two distinct molecular subgroups with opposite outcome. The C1A group of poor outcome ACC was characterized by numerous mutations and DNA methylation alterations, whereas the C1B group with good prognosis displayed a specific deregulation of two miRNA clusters. Thus, aggressive and indolent ACC correspond to two distinct molecular entities, driven by different oncogenic alterations.Array based dataset for this study has been made public at:http://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE49280.

  Study EGAS00001000665

• Genomic architecture and evolution of clear cell renal cell carcinomas defined by multiregion sequencing

  We applied multi-region exome sequencing to 10 clear cell renal carcinomas to resolve the genetic architecture, intra tumour heterogeneity and evolutionary histories of these tumours.

  Study EGAS00001000667

• Study on the consequences of prenatal famine exposure on DNA methylation.

  The potential of the epigenome to undergo environmentally-induced changes during early development is central to its postulated role in human disease. Here, we report a genome-scale view of DNA methylation differences after early gestational malnutrition that was caused by the Dutch Hunger Winter, a severe famine at the end of World War II. We adopted an annotation guided analysis of reduced-representation bisulfite sequencing data generated in 24 middle-aged individuals who had been exposed to famine in utero and 24 unexposed sibling controls. We observed differential DNA methylation primarily at genomic regions with regulatory potential, including enhancers active during early development. In-depth annotation of 181 prenatally-induced differentially methylated regions (P-DMRs) showed that they were predominantly located in gene bodies and co-occurred with histone marks denoting an active state. In line with the early gestational timing of the exposure, the P-DMRs mapped to genes that were enriched for differential expression patterns during blastocyst development and early organogenesis. Validation and further explorative analyses of 6 P-DMRs mapping to SMAD7, CDH23, INSR, RFTN1, CPT1A and KLF13 highlighted the critical role of gestational timing, indicated that differential methylation extended along pathways involved in growth, development and metabolism, and suggested associations with birth weight and serum LDL cholesterol in adulthood and confirmed an enhancer function for the INSR and CPT1A P-DMRs. Our results point toward a link between prenatal malnutrition and epigenetic modulation of growth and lipid metabolism that may underlie the adverse metabolic phenotype of exposed individuals in later life.

  Study EGAS00001000668

• Genome wide association study on coronary heart disease in patients with familial hypercholesterolemia

  Mutations in the low-density lipoprotein receptor (LDLR) gene cause familial hypercholesterolemia (FH), a disorder characterized by coronary heart disease (CHD) at young age. We aimed to apply an extreme sampling method to enhance the statistical power to identify novel genetic risk variants for CHD in individuals with FH. We selected cases and controls with an extreme contrast in CHD risk from 17 000 FH patients from the Netherlands, whose functional LDLR mutation was unequivocally established. The genome-wide association (GWA) study was performed on 249 very young FH cases with CHD and 217 old FH controls without CHD (above 65 years for males and 70 years of age for females) using the Illumina HumanHap 550K chip. In the next stage, two independent samples (one from the Netherlands and one from Italy, Norway, Spain, and the United Kingdom) of FH patients were used as replication samples. In the initial GWA analysis we identified 29 independent single nucleotide polymorphisms (SNPs) with suggestive associations with premature CHD (p<1×10-4). We examined the association of these SNPs with CHD risk in the replication samples. After Bonferroni correction, none of the SNPs either replicated or reached genome-wide significance after combining the discovery and replication samples. Therefore, we conclude that the genetics of CHD risk in FH is complex and even applying an ‘extreme genetics’ approach we did not identify new genetic risk variants. Most likely, this method is not as effective in leveraging effect size as anticipated, and may therefore not lead to significant gains in statistical power. (NB submitten and conditionally accepted at European Journal of Human Genetics-please use abstract only for internal review until submission complete)

  Study EGAS00001000734

• Next generation sequencing of sporadic schwannomatosis samples

  Schwannomatosis (MIM #162091) is characterized by the development of multiple schwannomas without vestibular nerve involvement (which is a characteristic of neurofibromatosis type 2 - NF2). In an effort to detect novel genetic alterations predisposing to schwannomatosis, we sequenced eight tumor-blood DNA pairs from de novo schwannomatosis patients. The results of our study are present in the paper "Whole exome sequencing reveals that the majority of schwannomatosis cases remain unexplained after excluding SMARCB1 and LZTR1 germline variants" published in Acta Neuropathologica (PMID:25008767)

  Study EGAS00001000767

• Systems biology of Colorectal Cancer

  Colorectal cancer (CRC) is one of the most common cancers in both males and females, and it is perhaps the best understood of all epithelial tumors in terms of its molecular origin. Yet, despite large amount of work that has concentrated on understanding of colon tumorigenesis, we still do not know the full complement of molecular lesions that are individually necessary – and together sufficient – to cause colorectal cancer. Neither do we understand why some specific mutations that are relatively rare in other tumors (e.g. loss of the APC tumor suppressor) are extremely common in colorectal cancer. We propose here to use the tools of systems biology to develop a quantitative and comprehensive model of colorectal tumorigenesis. The model will include identification of cell-type specific and oncogenic pathways that contribute to colon tumorigenesis, and explain in molecular detail how a genotype of an individual CRC leads to activation of downstream genes that drive uncontrolled cell growth. This model will subsequently be used to find novel therapeutic targets, to guide genetic screening to identify individuals with elevated risk for developing CRC, and to classify patients into molecular subgroups to select the treatment combination that is optimal for each patient (personalized medicine). The specific objectives of the SYSCOL project are: 1. Identify genetic markers for individual risk using genotyping and sequencing of constitutional DNA from sporadic and familial CRC cases and controls 2. Identify genes and regulatory elements that contribute to colorectal cancer cell growth 3. Use data from Aims 1-2 to develop a quantitative model for colorectal tumorigenesis 4. Apply the model for identification of high-risk individuals, for molecular classification of the disease, and for identification of novel molecular treatment targets

  Study EGAS00001000854

• Study on the proliferation history of colorectal adenomas

  Mismatch repair (MMR) deficient colorectal adenomas are composed of transformed cells that descend from a common founder and progressively accumulate genomic alterations but their proliferation history is still largely unknown. Here we rebuilt the proliferation history of four MMR deficient colorectal adenomas from male individuals by deep sequencing the X chromosome and mapping the somatic mutations that were progressively acquired during tumor growth. We developed a novel method to call high and low frequency mutations, to cluster them according to their frequencies and rebuild the proliferation trees directly from these mutation clusters using a recursive algorithm. The trees of all four lesions were formed of a dominant subclone that coexisted with other genetically heterogeneous subpopulations of cells. Despite this similar hierarchical organization, however, the growth dynamics varied among and within tumors, likely depending on a combination of tumor-specific genetic and environmental factors. Our study provides insights into the biological properties of individual MMR deficient colorectal adenomas that may influence their growth and also the response to therapy. Extended to other solid tumors, our approach could inform on the mechanisms of cancer progression, thus providing insight into the best choice of cancer treatment methods.

  Study EGAS00001000883

• Integrated genetic and epigenetic analysis defines novel molecular clusters in rhabdomyosarcoma

  Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in childhood. To unravel the genetic/epigenetic basis of RMS, we studied 60 RMS cases using whole exome/transcriptome sequencing, copy number (CN) profiling, and DNA methylome analysis. Based on DNA methylation patterns, RMS was clustered into 4 distinct subtypes, which exhibited remarkable correlation with mutation/CN profiles, histological phenotypes, and clinical behaviors. A1 and A2 subtypes, especially A1, largely corresponded to alveolar histology with frequent PAX3/7 fusions and alterations in cell cycle regulators. In contrast, mostly showing embryonal histology, both E1 and E2 subtypes were characterized by high frequency of CN alterations and/or allelic imbalances, FGFR4/RAS/AKT pathway mutations and PTEN mutations/methylation and in E2, also by p53 inactivation. Despite generally poor prognosis in RMS, patients in E1 cluster exceptionally showed excellent prognosis. Our results highlight the close relationship between DNA methylation status and gene mutations and biological behavior in RMS.

  Study EGAS00001000884

• Ischemic stroke in a Swedish case-control study.

  Background. Genetic risk scores (GRS), summing up the total effect of several single nucleotide polymorphisms (SNPs) in genes associated with either coronary risk or cardiovascular risk factors, have been tested for association with ischemic stroke with conflicting results. Recently an association was found between a GRS, based on 29 SNPs discovered by genome-wide association studies (GWAS) and hypertension. The aim of our study was to investigate the possible association of the same GRS with ischemic stroke on top of other “traditional risk factors”, also testing its potential improvement in indices of discrimination and reclassification, in a Swedish case-control study. Methods and results. Twenty-nine SNPs were genotyped in 3,677 stroke cases and 2,415 controls included in the Lund Stroke Register (LSR), the Malmö Diet and Cancer (MDC) study and the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS). The analysis was conducted in the entire material, and separately for the three samples. After adjustment for hypertension, diabetes mellitus and smoking habits, the GRS was associated with ischemic stroke in the entire material [OR (95% CI) 1.086 (1.029-1.147) per SD increase in the GRS p=0.003] with similar trends in all three samples; LSR [1.050 (0.967-1.140)]; p=0.25], MDC [1.168 (1.060-1.288); p=0.002] and SAHLSIS [1.124 (0.997-1.267); P=0.055]. Measures of discrimination and reclassification improved marginally using the GRS. Conclusions. A blood pressure GRS is independently associated with ischemic stroke risk in three Swedish case-control studies, however, the effect size is low and adds marginally to prediction of stroke on top of traditional risk factors including hypertension.

  Study EGAS00001000936

• Genomic analyses of gynecologic carcinosarcomas reveal frequent mutations in chromatin remodeling genes

  Malignant Mixed Müllerian Tumors, also known as carcinosarcomas, are rare tumors of gynecological origin. Here we perform whole exome analyses of 22 tumors using massively parallel sequencing to determine the mutational landscape of this tumor type. On average, we identify 43 mutations per tumor, excluding four cases with a mutator phenotype that harbored inactivating mutations in mismatch repair genes. In addition to mutations in TP53 and KRAS, we identify genetic alterations in chromatin remodeling genes, ARID1A and ARID1B, in histone methyltransferase MLL3, in histone deacetylase modifier SPOP, and in chromatin assembly factor BAZ1A, in nearly two thirds of cases. Alterations in genes with potential clinical utility are observed in more than three quarters of the cases and included members of the PI 3-kinase and homologous DNA repair pathways. These findings highlight the importance of the dysregulation of chromatin remodeling in carcinosarcoma tumorigenesis and suggest new avenues for personalized therapy.

  Study EGAS00001000941

• Clinical and Molecular Investigation of Familial CEBPA-mutated Acute Myeloid Leukaemia

  Myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML) are clonal diseases arising from the sequential acquisition of genetic aberrations in haematopoietic stem cells. Whilst the aetiology is predominantly sporadic, rare reports describe the autosomal dominant inheritance of MDS and AML (familial MDS/AML), often presenting in younger patients (<40 years of age) with a germline mutation in one of three haematopoietic transcription factors: RUNX1, CEBPA and GATA2. The clinical recognition of familial disease can be challenging due to wide variations in phenotype, latency and transmission, complicated further by the patients’ awareness and reporting of affected relatives. Distinct clinical manifestations have however been reported for each genetic subtype and whilst RUNX1 and GATA2 mutations can harbour prolonged dysplastic or cytopenic phases, germline CEBPA mutations universally present with AML de novo. Our group were the first to describe germline CEBPA mutations in 3 related individuals, all of whom developed AML between 10-30 years of age. The initial pedigree together with those described in the intervening period, were predominantly isolated case reports with limited follow up, hence long term outcomes for this group of patients remain poorly defined. This contrasts with CEBPA mutations occurring in 10-15% of sporadic AML with normal karytoype (NK-AML), where double mutations (CEBPAdm, found in approximately 50% of all CEBPA-AML) are considered a unique molecular entity, associated with favourable clinical outcomes. In sporadic and familial CEBPAdm AML, N’ terminal mutations enforce translation of the shorter P30-kDa isoform and are typically accompanied by C’ terminal insertions or deletions (disrupting the DNA-binding and/or Leucine zipper domains). Definition of the full molecular landscape awaits extensive whole exome sequencing, although GATA2 mutations (targeting the Zinc Finger 1, ZF1, domain) have been reported in 20-40% of sporadic CEBPAdm AML and recent targeted resequencing analysis revealed a further association with WT1 mutations. With minimal clinical and molecular information available for familial CEBPA-AML, we are often consulted regarding the management of this unique patient population. To address this need, we have investigated a multi-centre cohort of families with germline CEBPA mutations, providing extended clinical follow up, whole exome profiling of secondary mutations and molecular analysis of relapsed disease.

  Study EGAS00001000949

• BLUEPRINT ChIP-seq of Epigenetic programming during monocyte to macrophage differentiation and trained innate immunity

  Monocyte differentiation into macrophages represents a cornerstone process for host defense. Concomitantly, immunological imprinting of either tolerance or trained immunity determines the functional fate of macrophages and susceptibility to secondary infections. Transcriptomes and epigenomes in four primary cell types: monocytes, in vitro differentiated naïve, tolerized and trained macrophages were characterized. Inflammatory and metabolic pathways were modulated in macrophages, including decreased inflammasome activation, and pathways functionally implicated in trained immunity were identified. Strikingly, β-glucan training elicits an exclusive epigenetic signature, revealing a complex network of enhancers and promoters. Analysis of transcription factor motifs in DNase I hypersensitive sites at cell-type specific epigenetic loci unveiled differentiation and treatment specific repertoires. Altogether, this study provides a resource to understand the epigenetic changes that underlie innate immunity in humans.

  Study EGAS00001000951

• BLUEPRINT RNA-seq of Epigenetic programming during monocyte to macrophage differentiation and trained innate immunity

  Monocyte differentiation into macrophages represents a cornerstone process for host defense. Concomitantly, immunological imprinting of either tolerance or trained immunity determines the functional fate of macrophages and susceptibility to secondary infections. Transcriptomes and epigenomes in four primary cell types: monocytes, in vitro differentiated naïve, tolerized and trained macrophages were characterized. Inflammatory and metabolic pathways were modulated in macrophages, including decreased inflammasome activation, and pathways functionally implicated in trained immunity were identified. Strikingly, β-glucan training elicits an exclusive epigenetic signature, revealing a complex network of enhancers and promoters. Analysis of transcription factor motifs in DNase I hypersensitive sites at cell-type specific epigenetic loci unveiled differentiation and treatment specific repertoires. Altogether, this study provides a resource to understand the epigenetic changes that underlie innate immunity in humans.

  Study EGAS00001000953

• 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

• BLUEPRINT DNase accessibility of Epigenetic programming during monocyte to macrophage differentiation and trained innate immunity

  Monocyte differentiation into macrophages represents a cornerstone process for host defense. Concomitantly, immunological imprinting of either tolerance or trained immunity determines the functional fate of macrophages and susceptibility to secondary infections. Transcriptomes and epigenomes in four primary cell types: monocytes, in vitro differentiated naïve, tolerized and trained macrophages were characterized. Inflammatory and metabolic pathways were modulated in macrophages, including decreased inflammasome activation, and pathways functionally implicated in trained immunity were identified. Strikingly, β-glucan training elicits an exclusive epigenetic signature, revealing a complex network of enhancers and promoters. Analysis of transcription factor motifs in DNase I hypersensitive sites at cell-type specific epigenetic loci unveiled differentiation and treatment specific repertoires. Altogether, this study provides a resource to understand the epigenetic changes that underlie innate immunity in humans.

  Study EGAS00001000954

• Germline variants in the SEMA4A gene predispose to familial colorectal cancer type X

  Familial colorectal cancer type X (FCCTX) is characterized by clinical features of hereditary non-polyposis colorectal cancer with a yet undefined genetic background. Here, using an integrative genomics strategy, we identify the SEMA4A p.Val78Met germline mutation in an Austrian kindred with FCCTX. Compared with wild-type protein, SEMA4AV78M demonstrates significantly increased MAPK/Erk and PI3K/Akt signaling as well as cell cycle progression of SEMA4A deficient HCT-116 colorectal cancer cells. In a cohort of 53 patients with FCCTX we depict two further SEMA4A mutations, p.Gly484Ala and p.Ser326Phe, and the single nucleotide polymorphism (SNP) p.Pro682Ser. This SNP is highly associated with the FCCTX phenotype exhibiting increased risk for colorectal cancer (OR 6.79, 95% CI 2.63 to 17.52). Our study shows previously unidentified germline variants in SEMA4A predisposing to FCCTX which has implications for surveillance strategies of patients and their families.

  Study EGAS00001000957

• Genomic, transcriptomic and epigenomic profiling of GCTB

  Giant cell tumor of bone is a rare bone neoplasm driven by oncogenic hotspot G34W/L/V mutations in the non-canonical histone variant H3.3. This study provides primary data of genomic (WGS), transcriptomic (RNA-seq) and epigenomic (histone mark ChIP-seq, WGBS, ATAC-seq) profiling of primary GCTB samples from several cohorts in Germany and Korea. We confirm the H3.3-G34 mutations as sole genetic drivers of GCTB, and describe the epigenetic alterations in mutant GCTB stromal cells.

  Study EGAS00001003730

• Confirmation of a founder effect in a Northern European population (FRL) of a new beta-globin variant: HBB:c.23_26dup (codons 8/9 (+AGAA))

  Beta-thalassemia is a genetic disease caused by a defect in the production of the beta-like globin chain. More than 200 known different variants can lead to the disease and are mainly found in populations that have been exposed to malaria parasites. We recently described a duplication of 4 nucleotides in the first exon of beta-globin gene in several families of patients living in Nord-Pas-de-Calais (France). Using the genotypes at 12 microsatellite markers surrounding the beta-globin gene of four unrelated variant carriers plus an additional one recently discovered, we found that they shared a common haplotype indicating a founder effect that was estimated to have taken place 225 years ago (9 generations). In order to determine whether this variant arose in this region of Northern-Europe or was introduced by migrants from regions of the world where thalassemia is endemic, we genotyped the first 4 unrelated variant carriers and 32 controls from Nord-Pas-de-Calais for 97 European ancestry informative markers (EAIMs). Using these EAIMs and comparing with population reference panels, we demonstrated that the variant carriers were very similar to the controls and were closer to North European populations than to South European or Middle-East populations. Rare beta-thalassemia variants have already been described in patients sampled in non-endemic regions but it is the first proof of a founder effect in Northern Europe. The new genetic panel FRL is under registration in EGA.

  Study EGAS00001000980

• 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

• First genome-wide association study in an Australian Aboriginal population provides insights into genetic risk factors for Body Mass Index and Type 2 Diabetes

  A body mass index (BMI) >22kg/m2 is a risk factor for type 2 diabetes (T2D) in Aboriginal Australians. To identify loci associated with BMI and T2D we undertook a genome-wide association study using 1,355,133 quality-controlled single nucleotide polymorphisms (SNPs) genotyped (Illumina 2.5M Duo Beadchip) in 402 individuals in extended pedigrees from a Western Australian Aboriginal community. Imputation using the thousand genomes (1000G) reference panel extended the analysis to 6,724,284 post quality-control autosomal SNPs. No associations achieved genome-wide significance, commonly accepted as P<5x10-8. Nevertheless, genes/pathways in common with other ethnicities were identified despite the arrival of Aboriginal people in Australia >45,000 years ago. The top hit (rs10868204 Pgenotyped=1.50x10-6; rs11140653 Pimputed_1000G=2.90x10-7) for BMI lies 5’ of NTRK2, the type 2 neurotrophic tyrosine kinase receptor for brain-derived neurotrophic factor (BDNF) that regulates energy balance downstream of melanocortin-4 receptor (MC4R). PIK3C2G (rs12816270 Pgenotyped=8.06x10-6; rs10841048 Pimputed_1000G=6.28x10-7) was associated with BMI, but not with T2D as reported elsewhere. BMI also associated with CNTNAP2 (rs6960319 Pgenotyped=4.65x10-5; rs13225016 Pimputed_1000G=6.57x10-5), previously identified as the strongest gene-by-environment interaction for BMI in African-Americans. The top hit (rs11240074 Pgenotyped=5.59x10-6, Pimputed_1000G=5.73x10-6) for T2D lies 5’ of BCL9 that, along with TCFL2, promotes beta-catenin’s transcriptional activity in the WNT signaling pathway. Additional hits occurred in genes affecting pancreatic (KCNJ6, KCNA1) and/or GABA (GABRR1, KCNA1) functions. Notable associations observed for genes previously identified at genome-wide significance in other populations included MC4R (Pgenotyped=4.49x10-4) for BMI and IGF2BP2 Pimputed_1000G=2.55x10-6) for T2D. Our results may provide novel functional leads in understanding disease pathogenesis in this Australian Aboriginal population.

  Study EGAS00001001004