12277 results for ""statistically+reactive"+taxa+in+microbial+community"

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• CAF-S3 subset in human breast and ovarian cancers

  Carcinoma-associated fibroblasts (CAF) are key players in the tumor microenvironment. By combining 6 well-known stromal markers, we identify four CAF subsets (CAF-S1 to CAF-S4) in human breast and ovarian cancers.

  Study EGAS00001003344

• SNP array study in Autism Spectrum Disorder patients

  The aim of this study was to investigate two ancestral inversions (inv17q21.31 and inv8p23.1) in Autism Spectrum Disorder (ASD) patients. We have performed SNP array in order to genotype these inversions using the package scoreInvHap.

  Study EGAS00001005606

• germline variants in children with hematological cancer

  Trio parent-child whole exome sequencing has been used to identify cancer predisposing syndrome (CPS) in our pediatric patients with hematological cancer, and it was identified in 3.8% of the total number of patients(131).

  Study EGAS00001006907

• ARID1A Mutations in Endometriosis-Associated Ovarian Carcinomas

  We have sequenced the whole transcriptomes of 18 ovarian clear-cell carcinomas and 1 ovarian clear-cell carcinoma cell line and found somatic mutations in ARID1A (the AT-rich interactive domain 1A [SWI-like] gene) in 6 of the samples. ARID1A encodes BAF250a, a key component of the SWI–SNF chromatin remodeling complex. We sequenced ARID1A in an additional 210 ovarian carcinomas and a second ovarian clear-cell carcinoma cell line and measured BAF250a expression by means of immunohistochemical analysis in an additional 455 ovarian carcinomas

  Study EGAS00000000075

• Oral Microbiome in Esophageal Adenocarcinoma

  The purpose of our study was to assess the influence of oral microbiota on the development of esophageal cancer. Our preliminary case-control studies reported a global alteration of foregut microbiome in esophageal adenocarcinoma with the strongest changes found in the oral microbiome. We hypothesise that commensal oral bacteria are capable of activating or degrading carcinogens in cigarette smoke and therefore may contribute to esophageal carcinogenesis. We conducted a prospective study nested in two large US cohorts, to determine whether oral microbiota are associated with subsequent esophageal adenocarcinoma.

  Study phs001527

• NHLBI TOPMed: Children's Health Study (CHS) Integrative Genetic Approaches to Gene-Air Pollution Interactions in Asthma (GAP)

  The Integrative Genetic Approaches to Gene-Air Pollution Interactions in Asthma (GAP) study was proposed to use an innovative genetics approach in mice and humans to identify novel variants that interact with traffic-related pollutant exposures to affect lung function phenotypes and the risk of childhood asthma. The study participants were enrolled from the original southern California Children's Health Study (CHS). In the TOPMed project, seven Hispanic White participants who did not have asthma history were included in the WGS analysis.

  Study phs001602

• Differential Mutations in Matched Primary and Metastatic Colorectal Cancers

  This study compares DNA mutations detected in matched primary and metastatic colorectal cancer samples from 18 individuals across 1,321 genes. We found many more mutations were shared between tumor pairs (avg. 33.3 mutations/tumor) than were discordant (avg. 2.3 mutations / tumor). Nearly all tumors showed at least one discordance, and these were observed in genes known to be involved in colorectal cancer progression. Therefore, although primary and metastatic colorectal tumors are highly genetically concordant, evidence exists for discordance, which has clinical implications especially in situations of chemotherapy resistance or insensitivity.

  Study phs001084

• Metagenomic Deep Sequencing in Meningitis and Encephalitis

  This is a prospective observational study seeking to identify pathogens in cases of unexplained neurological disease, particularly those in which there is a presumed infectious cause. This next generation analytical approach will hopefully allow for rapid identification of foreign genomic material, and through a sophisticated bioinformatics pipeline developed in the DeRisi lab, these foreign genomic sequences can be aligned to all known sequences in publicly available databases (i.e. GenBank) which may allow for identification of novel pathogens or known pathogens that are not frequently tested for as part of standard diagnostic work-ups.

  Study phs001067

• Chromothripsis orchestrates leukemic transformation in blast phase MPN through targetable amplification of DYRK1A

  We describe recurrent chromothripsis and structural variation of chromosome 21 in a subset of patients in blast phase of a myeloproliferative neoplasm (BP-MPN), which alongside other structural variants leads to amplification of a region of chromosome 21 in ~25% of patients (‘chr21amp’). Chr21amp BP-MPN has a particularly aggressive and treatment-resistant phenotype. Here we provide high-depth whole genome sequencing (WGS) in five chr21amp BP-MPN cases, to a median coverage of 81x [range 77-86] and purity 79% [range 58-88%].

  Study EGAS00001007483

• Establishment of an integrated database for clinical and genomic data in cancer

  In this study, to clarify the genomic varieties of MM in Asian population, we planned to investigate the genomic features in Japanese population, represented as an Asian cohort, and preformed the comprehensive genomic analysis of MM cells with newly diagnosed multiple myeloma (NDMM) by means of targeted capture sequencing (TCS) method. In our TCS assay, MM cells are subjected to the detection of following genomic abnormalities; IG rearrangements, IG associated translocations, CNAs, and somatic mutations from 340 genes related to the pathogenesis and therapeutic agent of MM.

  Study JGAS000206

• CUT&Tag sequencing of ZFHX4 and H3K27ac in midbrain dopaminergic neurons.

  CUT&Tag sequencing of the transcription factor ZFHX4 and the histone mark H3K27ac was performed in midbrain dopaminergic neurons (mDANs) derived from induced pluripotent stem cells. This epigenomic approach enabled the identification of ZFHX4 binding sites in this specific cellular context. Comparing the CUT&Tag profiles of ZFHX4 and H3K27ac provided insights into epigenetic landscapes in mDANs and revealed whether ZFHX4 exhibits patterns similar to the active transcription mark H3K27ac. Finally, enrichment analysis of the identified peaks highlighted potential primary targets of ZFHX4 in mDANs.

  Study EGAS50000001112

• ScRNA-seq of PBMC and whole blood samples reveals a dysregulated myeloid cell compartment in severe COVID-19

  In a dual-center, two-cohort study, we performed single-cell RNA-sequencing of whole blood and peripheral blood mononuclear cells to determine changes in immune cell composition and activation in mild vs. severe COVID-19 over time. This study provides detailed insights into the systemic immune response to SARS-CoV-2 infection and reveals profound alterations in the myeloid cell compartment associated with severe COVID-19.

  Study EGAS00001004571

• Convergent somatic evolution from early life in a germline ribosomopathy

  Clonal tracking of stem cells and their progeny by whole genome sequencing permits exploration of evolutionary genetics in human disease. In this study, we performed phylogenetic reconstruction of haematopoiesis using somatically acquired mutations in 323 single haematopoietic stem and progenitor cell-derived colonies from 10 individuals with an inherited disorder of ribosome assembly, Shwachman-Diamond syndrome. We observed numerous clonal expansions, with recurrent acquisition of mutually exclusive mutations (EIF6, TP53, RPL5, RPL22, PRPF8, chromosomes 7 and 15) in multiple different clones in utero or early childhood converging on the p53-dependent nucleolar surveillance pathway that monitors ribosome integrity. In contrast to clones carrying biallelic TP53 mutations, genomes derived from colonies carrying mono-allelic TP53 mutations displayed no increase in mutation burden or specific mutational signatures. Our study highlights striking loss of clonal diversity with convergent somatic evolution on the p53-dependent nucleolar surveillance pathway from early life to offset the deleterious effects of a germline mutation in a Mendelian haematopoietic disorder.

  Dataset EGAD00001009061

• MGMT genomic rearrangements contribute to chemotherapy resistance in gliomas

  Temozolomide (TMZ) is an oral alkylating agent used for the treatment of glioblastoma and is now becoming a chemotherapeutic option in patients diagnosed with high-risk low-grade gliomas. The O-6-methylguanine-DNA methyltransferase (MGMT) is responsible for the direct repair of the main TMZ-induced toxic DNA adduct, the O6-Methylguanine lesion. MGMT promoter hypermethylation is currently the only known biomarker for TMZ response in glioblastoma patients. Here we show that a subset of recurrent gliomas carry MGMT genomic rearrangements that lead to MGMT overexpression, independently from changes in its promoter methylation. By leveraging the CRISPR/Cas9 technology we generated some of these MGMT rearrangements in glioma cells and demonstrated that they lead to TMZ resistance both in vitro and in vivo. Lastly we showed that such fusions can be detected in tumor-derived exosomes and could potentially represent an early detection marker of tumor recurrence in a subset of patients treated with TMZ.

  Dataset EGAD00001006281

• Kids First: Genetics of Pediatric Germ Cell Tumors

  The Gabriella Miller Kids First Pediatric Research Program (Kids First) is a trans-NIH effort initiated in response to the 2014 Gabriella Miller Kids First Research Act and supported by the NIH Common Fund. This program focuses on gene discovery in pediatric cancers and structural birth defects and the development of the Gabriella Miller Kids First Pediatric Data Resource (Kids First Data Resource). All of the genomic and phenotypic data from this study are accessible through dbGaP. The data is also available at the Kids First Portal, where other Kids First datasets can also be accessed in the cloud for data analysis, data visualization, collaboration and interoperability, open to all researchers and developers.Pediatric malignant germ cell tumors (GCTs) represent approximately 6% of childhood cancers, including 3% of tumors in children aged 0-14 years and 15% of tumors in adolescents. GCTs are heterogeneous and grouped together due to the presumed common cell of origin, the primordial germ cell (PGC). GCTs typically occur in the testes or ovaries; however, extragonadal GCTs can occur and are likely a result of abnormal germ cell migration during development. Evidence suggests that GCTs, including those diagnosed in adults, are initiated in utero. Thus, alterations in normal embryonic development are likely to be especially relevant to GCT etiology. Germline susceptibility has not been evaluated in an agnostic fashion in pediatric GCT, mainly due to a lack of an adequate number of samples; however, emerging evidence supports a genetic etiology.In the two Kids First GCT projects, we will evaluate genetic susceptibility to intracranial and extracranial GCT by sequencing probands and their unaffected parents. The goals of the project are to: 1) evaluate the contribution of rare genetic variants in GCT through the use of aggregate burden tests, focusing on genes and established regulatory regions; 2) identify de novo SNVs and CNVs in pediatric GCT using a case-parent triad design; and 3) identify molecular signatures in GCT tumor specimens, overall and by age group and tumor characteristics. Whole Genome Sequencing (WGS) data generated through the Gabriella Miller Kids First Pediatric Research Program will provide an opportunity to investigate the genetic origins of GCT in a diverse set of samples. Given the limited knowledge of GCT etiology and biology, the results of the proposed analyses are likely to have a big impact on the field.

  Study phs002322

• Identification of improved IL28B SNPs and haplotypes for prediction of drug response in treatment of hepatitis C using massively parallel sequencing in a cross-sectional European cohort

  The hepatitis C virus infects nearly 3% of the World’s population, causing severe liver disease in many. Standard of care therapy is currently pegylated interferon alpha and ribavirin (PegIFN/R), which is effective in less than half of those infected with the most common viral genotype. Two IL28B SNPs, rs8099917 and rs12979860, predict response to (PegIFN/R) therapy in treatment of hepatitis C virus infection. These SNPs were identified in genome wide analyses using Illumina genotyping chips. In people of European ancestry, there are 6 common (>1%) haplotypes for IL28B, one tagged by rs8099917 minor allele, four tagged by rs12979860. We used massive parallel sequencing of the IL28B and IL28A gene regions generated by PCR from pooled DNA samples from 100 responders and 99 non-responders to therapy, to identify common variants. Variants that had high odds ratios and were validated were then genotyped in a cohort of 905 responders and non-responders. Their predictive power was assessed, alone and in combination with HLA-C. Only SNPs in the IL28B linkage disequilibrium block predicted drug response. Eighteen SNPs were identified with evidence for association with drug response, and with a high degree of confidence in the sequence call. We found that two SNPs, rs4803221 (homozygote minor allele positive predictive value (PPV) of 77%) and rs7248668 (PPV 78%), predicted failure to respond better than the current best, rs8099917 (PPV 73%) and rs12979860 (PPV 68%) in this cross-sectional cohort. The best SNPs tagged a single common haplotype, haplotype 2. Genotypes predicted lack of response better than alleles. However, combination of IL28B haplotype 2 carrier status with the HLA-C C2C2 genotype, which has previousl y been reported to improve prediction in combination with IL28B, provides the highest PPV (80%). The haplotypes present alternative putative transcription factor binding and methylation sites. Massive parallel sequencing allowed identification and comparison of the best common SNPs for identifying treatment failure in therapy for HCV SNPs tagging a single haplotype have the highest PPV, especially in combination with HLA-C. The functional basis for the association may be due to altered regulation of the gene. These approaches have utility in improving diagnostic testing and identifying causal haplotypes or SNPs.

  Study EGAS00001000096

• POU4F3 mutation screening in Japanese hearing loss patients.

  A variant in a transcription factor gene, POU4F3, is responsible for autosomal dominant nonsyndromic hereditary hearing loss, DFNA15. To date, 14 variants, including a whole deletion of POU4F3, have been reported to cause HL in various ethnic groups. In the present study, genetic screening for POU4F3 variants was carried out for a large series of Japanese hearing loss (HL) patients to clarify the prevalence and clinical characteristics of DFNA15 in the Japanese population. Massively parallel DNA sequencing of 68 target candidate genes was utilized in 2,549 unrelated Japanese HL patients (probands) to identify genomic variations responsible for HL. The detailed clinical features in patients with POU4F3 variants were collected from medical charts and analyzed. Novel 12 POU4F3 likely pathogenic variants (six missense variants, three frameshift variants, and three nonsense variants) were successfully identified in 15 probands (2.5%) among 602 families exhibiting autosomal dominant HL, whereas no variants were detected in the other 1,947 probands with autosomal recessive or inheritance pattern unknown HL. To obtain the audiovestibular configuration of the patients harboring POU4F3 variants, we collected audiograms and vestibular symptoms of the probands and their affected family members. Audiovestibular phenotypes in a total of 24 individuals from the 15 families possessing variants were characterized by progressive HL, with a large variation in the onset age and severity with or without vestibular symptoms observed. Pure-tone audiograms indicated the most prevalent configuration as mid-frequency HL type followed by high-frequency HL type, with asymmetry observed in approximately 20% of affected individuals. Analysis of the relationship between age and pure-tone average suggested that individuals with truncating variants showed earlier onset and slower progression of HL than did those with non-truncating variants. The present study showed that variants in POU4F3 were a common cause of autosomal dominant HL.

  Study JGAS000093

• Dynamics of multiple resistance mechanisms in plasma DNA and their clinical implications for NSCLC patients receiving EGFR-targeted therapies

  Background:The development of resistance mechanisms to targeted therapies is complicated by underlying tumour heterogeneity. When multiple resistance mechanisms co-exist, identifying the dominant driver(s) is critical for selection of treatment. Patients and methods:We studied the relative dynamics of multiple oncogenic drivers and resistance mechanisms in 50 patients with EGFR-mutant non-small cell lung cancer (NSCLC), during treatment with gefitinib and hydroxychloroquine (NCT00809237). We performed digital PCR and targeted deep sequencing of cell-free DNA from longitudinal plasma samples from all patients, and shallow whole genome sequencing of serial samples from three patients who underwent histological transformation to small-cell lung cancer (SCLC). ResultsEGFR activating mutations were assessed in tumour samples and accurately identified in plasma samples of 95% of patients (41/43). We identified additional mutations including EGFR T790M (31/50, 62%), TP53 (23/50, 46%), PIK3CA (7/50, 14%), and PTEN (4/50, 8%), and tracked their relative levels in plasma. Patients with both TP53 and EGFR mutations detected in plasma pre-treatment tended to have worse overall survival than those where only EGFR was detected. The resistance-conferring EGFR T790M mutation was identified in 62% of the patients who progressed. Changes in relative levels of T790M and activating mutations in EGFR corresponded to clinical responses in two patients who were given sequential treatments. Patients who progressed without T790M detected in plasma had worse PFS during TKI continuation, and developed alternative resistance mechanisms, that could be identified in plasma DNA, including SCLC-associated copy number changes and TP53 mutations, that tracked with progression and response to subsequent therapies. Conclusion:Longitudinal analysis of multiple oncogenic drivers in ctDNA may help identifying dominant mechanisms of resistance to EGFR-targeted therapies, and highlight the importance of monitoring genetic events that are not direct drug targets but provide non-invasive molecular information that may guide clinical management.

  Study EGAS00001002908

• Genetic analysis of HLA and immune escape genes in Diffuse Large B-cell Lymphoma

  Fifty percent of diffuse large B-cell lymphoma (DLBCL) cases lack cell-surface expression of the class-I major histocompatibility complex (MHC-I), thereby escaping immune recognition by cytotoxic T cells. In order to comprehensively identify the mechanisms involved in MHC-I loss, we first performed immunophenotypic analysis of both MHC class-I and -II in 657 cases across the spectrum of B-NHL, revealing that loss of MHC-I, but not MHC-II, is preferentially restricted to DLBCL. We then used whole exome and targeted deep-sequencing to examine genes involved in MHC-I expression in 74 DLBCL samples representative of MHC-I positive and negative cases. We show here that somatic biallelic or monoallelic inactivation of B2M and/or HLA-I is present in 80.9% (34/42) of MHC-I negative tumors. Furthermore, 68.8% (22/32) of MHC-I positive DLBCLs also harbored monoallelic HLA-I genetic alterations (MHC-I positivemono) that lead to allelic imbalance, suggesting allele-specific inactivation. Both MHC-I negative and MHC-I positivemono cases showed a significantly higher mutational burden as well as a higher number of inferred neo-antigens, suggesting co-selection of HLA-I loss and sustained neo-antigen production. Interestingly, the analysis of > 500.000 individuals in two databases revealed homozygosity of germline HLA-I genes in 26-38% of DLBCL patients, a frequency significantly higher than that observed in any other cancer type. In mice, germinal-center B cells lacking HLA-I expression did not progress to lymphoma and were counterselected in the context of oncogene-driven lymphomagenesis, suggesting that additional events are needed to license immune evasion. These results suggest a multi-step process of HLA-I loss including both germ-line and somatic events in DLBCL development, and have direct implications for the pathogenesis and immunotherapeutic targeting of this disease.

  Study EGAS00001005054

• MalariaGEN case-control study in the Gambia

  MalariaGEN case-control study in the Gambia.

  Study EGAS00000000026

• Genomic Profiling of Peripheral T-cell Lymphoma

  Peripheral T-cell lymphomas (PTCLs) are malignant and highly aggressive hematologic tumors arising from mature post-thymic T cells. The diagnosis of PTCL includes diverse lymphoma subgroups, altogether accounting for about 15% of all non-Hodgkin lymphomas. Despite recent advances in uncovering the mutational landscape of PTCLs, the prognoses of most PTCLs remain poor. To overcome the limits of exome sequencing and identify new genomic abnormalities in PTCL, we performed RNAseq and whole genome sequencing. From our analyses, we identified a recurrent in-frame deletion (VAV1 Δ778-786) generated by a focal deletion-driven alternative splicing mechanism as well as novel VAV1 gene fusions (VAV1-THAP4, VAV1-MYO1F, and VAV1-S100A7). These genetic lesions result in increased activation of VAV1 catalytic-dependent (MAPK, JNK) and non-catalytic-dependent (nuclear factor of activated T cells, NFAT) VAV1 effector pathways. These results support an oncogenic role for VAV1 signaling in the pathogenesis of PTCL (Abate et al., 2017). Recently, we have also identified a novel chimeric oncogene, FYN-TRAF3IP2, in the RNA-seq and whole genome sequencing analyses. FYN-TRAF3IP2 leads to aberrant NF-κβ activity downstream of T-cell receptor signaling and induces NF-κβ-driven T-cell transformation when expressed in hematopoietic progenitors in mice. This novel gene fusion supports the oncogenic driver role of NF-κβ signaling in the pathogenesis of PTCL (Kim et al., in review).

  Study phs001962

• Genomic landscapes of endometrioid and mucinous ovarian cancers and morphologically similar tumor types

  While endometrioid and mucinous ovarian cancers represent nearly a quarter of ovarian cancers, their molecular characteristics and pathologic origins are poorly understood. To characterize the genomic and epigenomic alterations of these ovarian cancer subtypes and evaluate links to morphologically similar tumors from other sites, we performed sequence, copy number, mutation signature, rearrangement, and methylation analyses from tumor samples and matched normal tissues of 133 patients. These analyses included patients with ovarian endometrioid (n=44), ovarian mucinous (n=43), uterine endometrial (n=15), and gastrointestinal mucinous cancers (n=31). In addition to identifying genes previously known to be involved in these tumors, we identified alterations in RAD51C, NOTCH4, SMARCA1/4 and JAK1 in ovarian endometrioid, ESR1 in uterine endometrioid, and SMARCA4 in ovarian mucinous cancers. Whole genome sequencing revealed rearrangements involving PTEN, NF1, and NF2 in ovarian endometrioid tumors, and NF1 and MED1 in ovarian mucinous cancers. The number of alterations and affected genes in ovarian and uterine endometrioid cancers were similar as were genome-wide methylation profiles, suggesting that these tumors may have a similar tissue of origin. By contrast, methylation patterns in ovarian mucinous cancers were more similar to other gastrointestinal mucinous cancers, including mucinous cancers of the stomach, colon, and pancreas. These analyses provide insights into the genomic landscapes and origins of mucinous and endometrioid ovarian carcinomas, providing new avenues for early clinical intervention and management of patients with these cancers.

  Study EGAS50000000523

• Relapse CHL study

  Classical Hodgkin Lymphoma (CHL) is characterized by a complex tumor microenvironment (TME) that supports disease progression. While immune cell recruitment by Hodgkin and Reed–Sternberg (HRS) cells is well-documented, the role of non-malignant B cells in relapse remains unclear. Using single-cell RNA sequencing (scRNA-seq) on paired diagnostic and relapsed CHL samples, we identified distinct shifts in B cell populations, particularly an enrichment of naïve B cells and a reduction of memory B cells in early-relapse compared to late-relapse and newly diagnosed CHL. The enrichment of naïve B cells in early relapse biopsies was confirmed in independent validation cohorts using scRNA-seq and immunohistochemistry. Notably, naïve B cells in early-relapse samples exhibited high expression of LGALS9, an immunosuppressive molecule known to interact with T cell immunoglobulin and mucin domain 3 (TIM-3) on regulatory T cells (Tregs). Cell-cell interaction analysis revealed the importance of interactions between LGALS9+ naïve B cells and TIM-3+ Tregs in the early-relapse setting. Spatial analysis by imaging mass cytometry confirmed close proximity of LGALS9+ naïve B cells with TIM-3⁺ CD4⁺ T cells and HRS cells, pointing to their role in shaping an immunosuppressive niche. Our findings highlight a previously unrecognized population of LGALS9⁺ naïve B cells with immunoregulatory potential in early-relapse CHL and provide new insights into the spatial and transcriptional architecture of the relapsed TME in CHL.

  Study EGAS00001008222

• Targeted sequencing of candidate regions on chromosome 22q predisposing to multiple schwannomas

  Constitutional LZTR1 or SMARCB1 pathogenic variants have been found in ~86% of familial and ~40% of sporadic schwannomatosis cases. Hence, we performed massively parallel sequencing of the entire LZTR1, SMARCB1 and NF2 genomic loci in 35 individuals with schwannomas negative for constitutional first-hit pathogenic variants in the LZTR1/SMARCB1/NF2 coding sequences, however with 22q deletion and/or a different NF2 pathogenic variant in each tumor, including six cases with only one tumor available. Furthermore, we verified whether any other LZTR1/SMARCB1/NF2 (likely) pathogenic variant(s) could be found in 16 cases carrying a SMARCB1 constitutional variant in the 3’ untranslated region (3’-UTR) c.*17C>T, c.*70C>T or c.*82C>T. As no additional variants were found, functional studies were performed to clarify the effect of these 3’-UTR variants on the transcript. The 3’-UTR variants c.*17C>T and c.*82C>T showed pathogenicity by negatively affecting SMARCB1 transcript level. Two novel deep intronic SMARCB1 variants, c.500+883T>G and c.500+887G>A, resulting in out-of-frame missplicing of intron 4, were identified in two unrelated individuals. Further resequencing of the entire repeat - masked genomics sequences of chromosome 22q in individuals negative for pathogenic variants in the SMARCB1/LZTR1/NF2 coding- and non-coding regions revealed five potential schwannomatosis-predisposing candidate genes, i.e. MYO18B, NEFH, SGSM1, SGSM3 and SBF1, pending further verification.

  Study EGAS00001005680

• ATRX mutant neuroblastoma is sensitive to EZH2 inhibition via modulation of neuronal differentiation.

  Mutations and structural alterations of the SWI/SNF-like chromatin remodeler ATRX have been reported at high frequency in a number of adult and pediatric tumors1. However, the consequences of ATRX (Alpha Thalassemia/Mental Retardation, X-linked) mutations in cancer and their underlying epigenetic sensitivities remain ill defined. Particularly intriguing are the large N-terminal deletions of ATRX in neuroblastoma that generate in-frame fusion (IFF) proteins1–3 devoid of key chromatin interaction domains. Here we demonstrate that neuroblastoma cells harbouring ATRX IFFs have distinct gene expression programs compared to neuroblastoma cells that are wild type for ATRX. This is due in part to H3K27me3-mediated silencing of REST (RE1 Silencing Transcription Factor) target genes involved in neuronal differentiation. In turn, we find that ATRX IFF cells display exquisite sensitivity to EZH2 inhibition in both adherent and tumorsphere conditions, due in part to derepression of neurogenesis genes, including REST targets. Examination of the epigenomic landscape of a pediatric neuroblastoma tumor harboring an ATRX IFF revealed that H3K27me3 occupies a subset of REST target genes that are transcriptionally silenced, and are sensitive to EZH2 inhibition in our cell-based assays. Thus, our study greatly advances our understanding of indolent neuroblastoma and identifies EZH2 inhibition as a potential therapy for patients with ATRX mutant disease. Further, these studies may be applicable to other ATRX mutant pediatric malignancies, particularly those carrying similar structural alterations of ATRX.

  Study EGAS00001002507