Affymetrix SNP array data for breast cancer samples
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE48377 | GEO | 2013/06/29
SECONDARY ACCESSION(S): PRJNA209971
REPOSITORIES: GEO
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Project description:Chromosomal structural mutations play an important role in determining the transcriptional landscape of human breast cancers. We determined that pro-oncogenic and anti-oncogenic genes are clustered throughout the genome and that these clusters coincide with regions of segmental amplification and deletion. We constructed detailed structural mutation maps of representative breast cancers and found that tandem duplications appear to nucleate regions for amplification. Subsequent rearrangements link distant pro-oncogenic elements for co-amplification, and are associated with loss of tumor suppressors. We show that genes engaged in co-amplifications or conjoint deletions on 17q and 8q have pro-growth effects that are additive in nature. Our results suggest structural mutations efficiently orchestrate the gain and loss of cancer gene cassettes that engage many oncogenic pathways simultaneously. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from fresh-frozen breast tumors with >80% tumor cell content and their paired peripheral blood samples. Copy number analysis of the SNP arrays was done using the copy number pipeline implemented into Partek software version 6.5
2013-06-29 | E-GEOD-48377 | biostudies-arrayexpress
Project description:Chromosomal structural mutations play an important role in determining the transcriptional landscape of human breast cancers. To assess the nature of these structural mutations, we analyzed a representative sampling of the major types of breast tumor samples for detailed structural mutations using paired-end tag sequencing of long-insert genomic DNA (DNA-PET) with matched transcriptome ascertainment by RNA-seq. Compared with other structural mutations, tandem duplications are enriched around partners of fusion transcripts and demarcate regions of high gene expression. Moreover tandem duplications appear to be early events in tumor evolution by facilitating subsequent downstream amplification and deletion of important adjacent cancer associated genes. In a detailed reconstruction of events in chr17, we found large unpaired-inversions connect a duplicated ERBB2 with neighboring 17q21.3 amplicons while simultaneously deleting the intervening BRCA1 tumor suppressor locus. Using siRNAs in breast cancer cell lines, we showed that the 17q21.3 amplicon harbored a significant number of weak oncogenes that appeared consistently co-amplified in primary tumors. Down-regulation of BRCA1 expression augmented the cell proliferation in human normal mammary epithelial cells. Finally, using in silico approaches, we determined that genes whose expression in breast tumors are associated with either poor or good clinical prognosis appear clustered together in segments of frequent amplification or deletion, suggesting that structural abnormalities induce the loss or gain of blocks of adjacent genes with oncogenic or growth suppressor function. These analyses suggest that structural mutations efficiently orchestrate the gain and loss of cancer gene cassettes that engage many oncogenic pathways simultaneously. RNA sequencing of four primary breast cancer RNA samples (SOLiD, Applied Biosystems).
2014-07-01 | E-GEOD-57914 | biostudies-arrayexpress
Project description:Chromosomal structural mutations play an important role in determining the transcriptional landscape of human breast cancers. To assess the nature of these structural mutations, we analyzed a representative sampling of the major types of breast tumor samples for detailed structural mutations using paired-end tag sequencing of long-insert genomic DNA (DNA-PET) with matched transcriptome ascertainment by RNA-seq. Compared with other structural mutations, tandem duplications are enriched around partners of fusion transcripts and demarcate regions of high gene expression. Moreover tandem duplications appear to be early events in tumor evolution by facilitating subsequent downstream amplification and deletion of important adjacent cancer associated genes. In a detailed reconstruction of events in chr17, we found large unpaired-inversions connect a duplicated ERBB2 with neighboring 17q21.3 amplicons while simultaneously deleting the intervening BRCA1 tumor suppressor locus. Using siRNAs in breast cancer cell lines, we showed that the 17q21.3 amplicon harbored a significant number of weak oncogenes that appeared consistently co-amplified in primary tumors. Down-regulation of BRCA1 expression augmented the cell proliferation in human normal mammary epithelial cells. Finally, using in silico approaches, we determined that genes whose expression in breast tumors are associated with either poor or good clinical prognosis appear clustered together in segments of frequent amplification or deletion, suggesting that structural abnormalities induce the loss or gain of blocks of adjacent genes with oncogenic or growth suppressor function. These analyses suggest that structural mutations efficiently orchestrate the gain and loss of cancer gene cassettes that engage many oncogenic pathways simultaneously.
2014-07-01 | GSE57914 | GEO
Project description:DNA amplification, particularly of chromosomes 8 and 11, occurs frequently in breast cancer and is a key factor in tumorigenesis, often associated with poor prognosis. The mechanisms involved in the amplification of these regions are not fully understood. Studies from model systems have demonstrated that palindrome formation can be an early step in DNA amplification, most notably seen in the breakage-fusion-bridge (BFB) cycle. Therefore, palindromes might be associated with gene amplicons in breast cancer. To address this possibility, we coupled high-resolution palindrome profiling by the Genome-wide Analysis of Palindrome Formation (GAPF) assay with genome-wide copy-number analyses on a set of breast cancer cell lines and primary tumors to spatially associate palindromes and copy-number gains. We identified GAPF-positive regions distributed non-randomly throughout cell line and tumor genomes, often in clusters and associated with copy-number gains. Commonly amplified regions in breast cancer, chromosomes 8q and 11q, had GAPF-positive regions flanking and throughout the copy-number gains. We also identified amplification-associated GAPF-positive regions at similar locations in subsets of breast cancers with similar characteristics (e.g., ERBB2 amplification). These shared positive regions offer the potential to evaluate the utility of palindromes as prognostic markers, particularly in premalignant breast lesions. Our results implicate palindrome formation in the amplification of regions with key roles in breast tumorigenesis, particularly in subsets of breast cancers.
2011-06-13 | GSE29876 | GEO
Project description:Neuroblastoma in advanced stages is among the most intractable pediatric cancers, even with the recent therapeutic advances. Neruroblastoma harbours a variety of genetic changes, including a high frequency of MYCN amplification, loss of heterozygosity in 1p36 and 11q, and gain of genetic material from 17q, all of which have been implicated in the pathogenesis of neuroblastoma. However, the scarcity of reliable molecular targets has hampered the development of effective therapeutic agents targeting neuroblastoma. We performed a genome-wide analysis of a large number of neuroblastoma samples, consisting of varying disease stages, permitted us to obtain a comprehensive registry of genomic lesions in neuroblastoma.
2008-10-10 | GSE12494 | GEO
Project description:Fallopian tube carcinoma (FTC) is a rare, poorly studied and aggressive cancer, associated with poor survival. Since tumorigenesis is related to acquisition of genetic changes, we used genome-wide array CGH to analyze copy number aberrations occurring in FTC in order to obtain a better understanding of FTC carcinogenesis and to identify prognostic events and targets for therapy. We used arrays of 2464 genomic clones, providing ~1.4 Mb resolution across the genome to quantitatively map genomic DNA copy number aberrations from fourteen FTC onto the human genome sequence. All tumors showed a high frequency of copy number aberrations with recurrent gains on 3q, 6p, 7q, 8q, 12p, 17q, 19 and 20q, and losses involving chromosomes 4, 5q, 8p, 16q, 17p, 18q and X. Recurrent regions of amplification included 1p34, 8p11-q11, 8q24, 12p, 17p13, 17q12-q21, 19p13, 19q12-q13 and 19q13. Candidate, known oncogenes mapping to these amplicons included CMYC (8q24), CCNE1 (19q12-q21) and AKT2 (19q13), whereas PIK3CA and KRAS, previously suggested to be candidate driver genes for amplification mapped outside copy number maxima on 3q and 12p, respectively. The FTC were remarkably homogeneous, with some recurrent aberrations occurring in more than 70% of samples, which suggests a stereotyped pattern of tumor evolution. Keywords: array CGH, CCNE1, AKT2, Fallopian tube cancer
2007-03-06 | GSE7180 | GEO
Project description:Recent insights into the role of the VHL tumor suppressor gene in hereditary and sporadic clear cell carcinoma of the kidney (ccRCC) have led to new treatments for patients with metastatic ccRCC, although virtually all patients eventually succumb to the disease. We performed an integrated, genome-wide analysis of copy-number changes and gene expression profiles in 90 tumors, including both sporadic and VHL disease-associated tumors, in hopes of identifying new therapeutic targets in ccRCC. We identified 14 regions of nonrandom copy-number change, including 7 regions of amplification (1q, 2q, 5q, 7q, 8q, 12p, and 20q) and 7 regions of deletion (1p, 3p, 4q, 6q, 8p, 9p, and 14q). An analysis aimed at identifying the relevant genes revealed VHL as one of 3 genes in the 3p deletion peak, CDKN2A and CDKN2B as the only genes in the 9p deletion peak, and MYC as the only gene in the 8q amplification peak. An integrated analysis to identify genes in amplification peaks that are consistently overexpressed among amplified samples confirmed MYC as a potential target of 8q amplification and identified candidate oncogenes in the other regions. A comparison of genomic profiles revealed that VHL disease-associated tumors are similar to a subgroup of sporadic tumors, and thus more homogeneous overall. Sporadic tumors without evidence of biallelic VHL inactivation fell into 2 groups: one group with genomic profiles highly dissimilar to the majority of ccRCC, and a second group with genomic profiles that are much more similar to tumors with biallelic inactivation of VHL. Keywords: comparative genomic hybridization
2009-06-02 | GSE14994 | GEO
Project description:Gene expression analysis was performed on 30 Neuroblastomas to identify genes whose transcription is significantly altered by recurrent chromosomal alterations. Genomic copy number losses and gains had been delineated in the tumours using FISH and SNP arrays. We have identified genes significantly altered by 7 recurrent alterations: 1p, 3p, 4p, 10q and 11q loss, 2p and 17q gain, and genes co-amplified and over-expressed as a result of MYCN amplification. Subsequently, correlation of microarray data with survival and expression within rodent neuroblastomas were used to identify genes likely to be involved in the disease progression, and identified a significant excess of differentially expressed genes which correlated with survival within the minimally altered regions on 17q and 4p; Identifying genes whose expression is consistently altered by chromosomal gains or losses is an important step in defining genes of biological relevance in a wide variety of tumour types. However, additional criteria are needed to discriminate further among the large number of candidate genes identified. This is particularly true for neuroblastoma, where multiple genomic copy number changes of proven prognostic value exist. We have used Affymetrix microarrays and a combination of fluorescent in-situ hybridisation and single nucleotide polymorphism (SNP) microarrays to establish expression profiles and delineate copy number alterations in 30 primary neuroblastomas. Correlation of microarray data with patient survival and analysis of expression within rodent neuroblastoma cell lines were then used to further define genes likely to be involved in the disease process. Using this approach we identify >1000 genes within 8 recurrent genomic alterations (loss of 1p, 3p, 4p, 10q and 11q, 2p gain, 17q gain, and the MYCN amplicon) whose expression is consistently altered by copy number change. Of these, 84 correlate with patient survival, with the minimal regions of 17q gain and 4p loss being significantly enriched for such genes. Orthologues of all but one of these genes on 17q are overexpressed in rodent neuroblastoma cell lines. A significant excess of SNPs whose copy number correlates with survival is also observed on proximal 4p in stage 4 tumours, and we find that deletion of 4p is associated with improved outcome in an extended cohort of tumours. These results define the major impact of genomic copy number alterations upon transcription within neuroblastoma, and highlight genes on distal 17q and proximal 4p for downstream analyses. They also suggest that integration of discriminators such as survival and comparative gene expression with microarray data may be useful in the identification of critical genes within regions of loss or gain in many human cancers. Experiment Overall Design: Chromosomal gains and losses were delineated in Stage 4 neuroblastomas to facilitate, in combination with expression array data, the identification of genes within regions of gain and loss whose expression is significantly altered by copy number change.
2008-10-26 | E-GEOD-13137 | biostudies-arrayexpress
Project description:In this study we have identified a new morphological pattern in IMPC defined by the presence of numerous bi-nucleated cells, related to abnormal expression of genes involved in regulation of mitosis. We also demonstrated that IMPC presented tight and adherens junctions proteins expression modifications that could participate to their clinical behavior. We showed that IMPC was associated with a specific genomic profile compared to ER+ grade-matched IDC consisting of gains of 17q, high rates of 17q23 and 17q12 ERBB2 amplifications, losses of heterozygosity of 6q. The putative role of the genes located in this 6q LOH should be further investigated in order to determine if they could play a role in the presence of numerous bi-nucleated cells and inverted polarity of IMPC cells. In addition, we identified two genomic IMPC subsets: the first characterized by numerous amplicons with frequently near-tetraploid cells and the second, associated with different complex gains and losses in addition to 8q gains and 16q losses, and predominantly composed of near-diploïd cells. The observation of two genomic subsets within the IMPC entity suggests the existence of two possible oncogenic mechanisms leading to the development of a single disease. Phenotypical analysis was combined with copy number, genotyping (SNP6.0 Affymetrix) and transcriptomic analyses in a series of 39 pure IMPC. The results were compared to those of 27 ER and grade-matched invasive ductal carcinomas (IDC).
2014-04-01 | E-GEOD-37035 | biostudies-arrayexpress
Project description:Chromosome as oncogenic organizer: functional consequences of focal amplification shaped by structural mutations in breast cancer
| PRJNA234462 | ENA