Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

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Genotype profiling of a primitive neuroectodermal tumour identifies a non-constitutive chr19q13.41 amplicon

ABSTRACT: Primitive neuro-ectodermal tumours (PNET) of the supratentorial region are rare, highly malignant embryonal brain tumours affecting young children. Although supratentorial PNET (sPNET) are histologically similar to infratentorial PNET/medulloblastoma, sPNET have more aggressive clinical phenotypes, which suggest sPNET represents distinct biological entities. In contrast to considerable progress in understanding the signalling pathways involved in medulloblastoma, little is known about sPNET pathogenesis. Here we identify a focal amplicon on chr19q13.41 that houses two polycistronic microRNA clusters. Functional analysese indicates that the microRNA clusters may promote oncogenesis in part by modulating cell survival. Copy number analysis was also performed on an overlapping set of PNET tumours, also available on GEO with accession code GSE14087. Keywords: single nucleotide polymorphism array, pediatric brain cancer A primitive neuroectodermal tumour sample with matched blood from the University of Cambridge was analyzed on the Affymetrix GeneChip Mapping 250K Nsp SNP array.

ORGANISM(S): Homo sapiens

SUBMITTER: Charles Eberhart

PROVIDER: E-GEOD-14248 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Frequent amplification of a chr19q13.41 microRNA polycistron in aggressive primitive neuroectodermal brain tumors.

Li Meihua M Lee Kyle F KF Lu Yuntao Y Clarke Ian I Shih David D Eberhart Charles C Collins V Peter VP Van Meter Tim T Picard Daniel D Zhou Limei L Boutros Paul C PC Modena Piergiorgio P Liang Muh-Lii ML Scherer Steve W SW Bouffet Eric E Rutka James T JT Pomeroy Scott L SL Lau Ching C CC Taylor Michael D MD Gajjar Amar A Dirks Peter B PB Hawkins Cynthia E CE Huang Annie A

Cancer cell 20091201 6

We discovered a high-level amplicon involving the chr19q13.41 microRNA (miRNA) cluster (C19MC) in 11/45 ( approximately 25%) primary CNS-PNET, which results in striking overexpression of miR-517c and 520g. Constitutive expression of miR-517c or 520g promotes in vitro and in vivo oncogenicity, modulates cell survival, and robustly enhances growth of untransformed human neural stem cells (hNSCs) in part by upregulating WNT pathway signaling and restricting differentiation of hNSCs. Remarkably, the ...[more]

PMID: 19962671

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Project description:Primitive neuro-ectodermal tumours (PNET) of the supratentorial region are rare, highly malignant embryonal brain tumours affecting young children. Although supratentorial PNET (sPNET) are histologically similar to infratentorial PNET/medulloblastoma, sPNET have more aggressive clinical phenotypes, which suggest sPNET represents distinct biological entities. In contrast to considerable progress in understanding the signalling pathways involved in medulloblastoma, little is known about sPNET pathogenesis. Prior low resolution CGH (comparative genomic hybridization) studies indicate sPNET have frequent genomic imbalances and copy number aberrations (CNAs). To define genes involved in sPNET pathogenesis, we utilized the Affymetrix 250K Nsp SNP (single nucleotide polymorphism) analysis to identify genes targeted by recurrent CNAs in primary human sPNET samples. Copy number analysis was conducted on 39 primary PNET samples. Select target genes were validated by genomic and/or RT-PCR. Our analysis revealed frequent CNA across the sPNET genome, encompassing large and focal chromosome segments, and corroborated previous reports that isochromosome 17q, an abnormality found in ~ 30% of medulloblastoma, is rare in sPNET. Keywords: single nucleotide polymorphism array, disease state analysis A total of 56 primary sPNET samples were collected for this study from The Hospital for Sick Children, John Hopkins University, St. Jude Research Hospital, University of Cambridge, Children’s Hospital Boston, Virginia Commonwealth University, Instituto nazionale per lo studio e la cura dei tumori, and Texas Children’s Hospital, with local Institutional Research Ethics Board approval. Pineoblastoma and rhaboid tumours were specifically excluded, leaving 52 samples, 39 of which had good quality DNA available. These samples, in addition to 28 diploid reference samples (a gift from Dr. S. Scherer, University of Toronto), were analyzed on the Affymetrix GeneChip Mapping 250K Nsp SNP array. Due to sample availability at the time the arrays were run, the diploid reference samples analyzed on the Sty arrays are different from reference samples analyzed on the Nsp arrays.

Project description:Preimplantation genetic diagnosis (PGD) of aneuploidy by fluorescence in situ hybridisation (FISH) has not delivered the expected clinical benefit. Many previous re-analysis studies of embryos deemed aneuploid by FISH on day 3 have found a high degree of chromosomal normalcy at the blastocyst stage. While most have interpreted this as âself correction,â there remains a lack of evidence for such a phenomenon. A more comprehensive technique for 24 chromosome aneuploidy screening was utilised here to re-evaluate blastocysts previously diagnosed as abnormal by FISH and investigate possible self correction mechanisms, including extrusion or duplication of aneuploid chromosomes resulting in uniparental isodisomy (UPID), and preferential segregation of aneuploidy to the trophectoderm (TE). Embryos that developed to a morphologically normal blastocyst after an aneuploidy diagnosis by cleavage stage FISH were biopsed into 4 sections, 3 TE and 1 inner cell mass (ICM), and randomised for evaluation by single nucleotide polymorphism (SNP) microarray based 24 chromosome aneuploidy screening (MA-PGD). Fifty-eight percent of blastocysts were euploid for all 24 chromosomes despite an aneuploid FISH result on day 3. Only 18% were consistent with the original FISH diagnosis, while the remaining 24% identified abnormalities that were different from the original FISH diagnosis. Abnormalities did not preferentially segregate to the TE and aneuploid chromosome extrusion or duplication resulting in UPID did not occur. Cleavage stage FISH is poorly predictive of aneuploidy in an embryo that develops into a morphologically normal blastocyst. Clinicians should consider re-evaluating embryos diagnosed as aneuploid by FISH that form morphologically normal blastocysts using a validated comprehensive 24 chromosome aneuploidy screening method. Affymetrix SNP arrays were processed according to the manufacturer's directions on DNA extracted from 50 cryopreserved blastocysts that were biopsied into 3 sections of trophectoderm and 1 inner cell mass section. Affymetrix SNP array analysis was successfully completed on 145 trophectoderm samples and 47 ICM samples from embryos, 8 lymphocyte samples from cell lines and 6 mixed male and female samples.

Project description:A common aim of pharmacogenomic studies that employ genome-wide assays on panels of cancers is the unbiased discovery of genomic alterations that are associated with clinical outcome and drug response. Previous investigations of lapatinib, a selective dual-kinase inhibitor of EGFR and HER2 tyrosine kinases, have demonstrated predictable relationships between the activity of these genes and response. Under the hypothesis that additional genes may play a role in promoting sensitivity, a predictive model for lapatinib sensitivity was constructed from genome-wide DNA copy number data from 24 cancer cell lines. An optimal predictive model, which consists of aberrations at nine distinct genetic loci, includes gains of HER2, EGFR, and loss of CDKN2A. This model, which achieved area under the Receiver Operating Characteristic (ROC) curve of ~0.85 (80% confidence interval: 0.70–0.98; P<0.01), and correctly classified the sensitivity status of 8/10 head and neck cancer cell lines. This study demonstrates that previously described biomarkers of lapatinib sensitivity, including copy number gains of EGFR and HER2, can be discovered as powerful predictors of response using novel genomic assays in an unbiased manner. Further, these results demonstrate the utility of DNA copy number profiles in pharmacogenomic studies. Keywords: Comparative Genomic Hybridization Basal DNA copy number profiles were derived from Affymetrix 'SNP chips' for a panel of 34 tumor derived cell lines. Each of these cell lines were tested for their degree of sensitivity to lapatinib. Specific DNA alterations associating with lapatinib sensitivity were identified using a training set consisting of 24 of these lines. A predictive model was constructed from these loci. The remaining 10 lines were used to test the model performance. A panel of chips (n = 12) assayed with germline DNA served as a reference in order to calculate the test/reference ratios reported in the Sample table VALUE columns. The 'reference' Samples for the 500K and 100K assays are as follows: 500K: GSM188024, GSM188025, GSM188026, GSM188027, GSM188028, GSM188029, GSM188030, GSM188031, GSM188032, GSM188033, GSM188034, GSM188035, GSM188048, GSM188049, GSM188050, GSM188051, GSM188052, GSM188053, GSM188054, GSM188055, GSM188056, GSM188057, GSM188058, GSM188059 100K: GSM187950, GSM187951, GSM187952, GSM187953, GSM187954, GSM187955, GSM187956, GSM187957, GSM187958, GSM187959, GSM187960, GSM187961, GSM187949, GSM187948, GSM187946, GSM187947, GSM187945, GSM187944, GSM187943, GSM187942, GSM187941, GSM187940, GSM187939, GSM187938

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Dataset Information

Genotype profiling of a primitive neuroectodermal tumour identifies a non-constitutive chr19q13.41 amplicon

Publications

Frequent amplification of a chr19q13.41 microRNA polycistron in aggressive primitive neuroectodermal brain tumors.

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