CDNA aCGH study of whole genome amlification effect on analysis of FFPE microdissected human breast cancer
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE10456 | GEO | 2008/02/10
SECONDARY ACCESSION(S): PRJNA108011
REPOSITORIES: GEO
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Project description:To investigate the cytogenetic and large-scale chromosomal changes in involuted or non-involuted microGISTs using post-whole genome amplification (WGA) FFPE DNA materials Sixteen patients, total 19 FFPE tumor samples (block storage time 4 months to 9 years), including 16 microGISTs and 3 GISTs larger than 1 cm from the same patients harboring microGISTs. All FFPE tumor samples underwent DNA extraction and WGA (modified degenerate oligonucleotide PCR (DOP) method, provided by Sigma). For each tumor sample, a post-WGA DNA extract from the normal tissue in the same block (or block from the same patient with a block storage time differences less than 2 years) was obtained for tumor sample DNA co-hybridization. Tumor and normal areas of interest were marked and collected from 5- to 10-micron unstained or hematoxylin-stained sections by manual or laser (PixCell IITM, Arcturus Bioscience, CA, USA) microdissection. DNAs were then extracted. WGA was performed using GenomePlex® Tissue Whole Genome Amplification WGA5 kit (Sigma, Saint Louis, MO, USA; http://www.sigmaaldrich.com/) in parallel in accordance with the manufacturer's protocols. At least four independent experiments were concurrently performed per template amplification. Four separate WGA reaction products were pooled for each sample.
2011-12-31 | E-GEOD-28469 | biostudies-arrayexpress
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2011-12-19 | GSE29227 | GEO
Project description:Whole-genome array comparative genomic hybridization (aCGH) of human ependymoma tumors. DOP-PCR products were spotted in triplicate onto NexterionTM Slide E epoxysilane-coated slides (PEQLAB, Erlangen, Germany) using a spotting robot (VersArray ChipWriterTM Pro system,BioRad, Munich, Germany) at 20C and 40% humidity. After spotting, slides were cross-linked,baked for 1 hr at 80C, and cross-linked again. Fresh frozen tumor material was collected during tumor resection. Copy number aberrations represent the status at diagnosis.
2011-08-14 | E-GEOD-27286 | biostudies-arrayexpress
Project description:Abstract: BACKGROUND: T7 based linear amplification of RNA is used to obtain sufficient antisense RNA for microarray expression profiling. We optimized and systematically evaluated the fidelity and reproducibility of different amplification protocols using total RNA obtained from primary human breast carcinomas and high-density cDNA microarrays. RESULTS: Using an optimized protocol, the average correlation coefficient of gene expression of 11,123 cDNA clones between amplified and unamplified samples is 0.82 (0.85 when a virtual array was created using repeatedly amplified samples to minimize experimental variation). Less than 4% of genes show changes in expression level by 2-fold or greater after amplification compared to unamplified samples. Most changes due to amplification are not systematic both within one tumor sample and between different tumors. Amplification appears to dampen the variation of gene expression for some genes when compared to unamplified poly(A)+ RNA. The reproducibility between repeatedly amplified samples is 0.97 when performed on the same day, but drops to 0.90 when performed weeks apart. The fidelity and reproducibility of amplification is not affected by decreasing the amount of input total RNA in the 0.3-3 micrograms range. Adding template-switching primer, DNA ligase, or column purification of double-stranded cDNA does not improve the fidelity of amplification. The correlation coefficient between amplified and unamplified samples is higher when total RNA is used as template for both experimental and reference RNA amplification. CONCLUSION: T7 based linear amplification reproducibly generates amplified RNA that closely approximates original sample for gene expression profiling using cDNA microarrays. This SuperSeries is composed of the SubSeries listed below.
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Project description:Title: Array-based gene expression, CGH and tissue data define a 12q24 gain in neuroblastic tumors with prognostic implication. Background: Neuroblastoma has successfully served as a model system for the identification of neuroectoderm-derived oncogenes. However, in spite of various efforts, only a few clinically useful prognostic markers have been found. Here, we present a framework, which integrates DNA, RNA and tissue data to identify and prioritize genetic events that represent clinically relevant new therapeutic targets and prognostic biomarkers for neuroblastoma. Methods: A single-gene resolution aCGH profiling was integrated with microarray-based gene expression profiling data to distinguish genetic copy number alterations that were strongly associated with transcriptional changes in two neuroblastoma cell lines. FISH analysis using a hotspot tumour tissue microarray of 37 paraffin-embedded neuroblastoma samples and in silico data mining for gene expression information obtained from previously published studies including up to 445 healthy nervous system samples and 123 neuroblastoma samples were used to evaluate the clinical significance and transcriptional consequences of the detected alterations and to identify subsequently activated gene(s). Results: In addition to the anticipated high-level amplification and subsequent overexpression of MYCN, MEIS1, CDK4 and MDM2 oncogenes, the aCGH analysis revealed numerous other genetic alterations, including microamplifications at 2p and 12q24.11. Most interestingly, we identified and investigated the clinical relevance of a previously poorly characterized amplicon at 12q24.31. FISH analysis showed low-level gain of 12q24.31 in 14 of 33 (42%) neuroblastomas. Patients with the low-level gain had an intermediate prognosis in comparison to patients with MYCN amplification (poor prognosis) and to those with no MYCN amplification or 12q24.31 gain (good prognosis) (P = 0.001). Using the in silico data mining approach, we identified elevated expression of five genes located at the 12q24.31 amplicon in neuroblastoma (DIABLO, ZCCHC8, RSRC2, KNTC1 and MPHOSPH9). Among these, DIABLO showed the strongest activation suggesting a putative role in neuroblastoma progression. Conclusions: The presented systematic and rapid framework, which integrates aCGH, gene expression and tissue data to obtain novel targets and biomarkers for cancer, identified a low-level gain of the 12q24.31 as a potential new biomarker for neuroblastoma progression. Furthermore, results of in silico data mining suggest a new neuroblastoma target gene, DIABLO, within this region, whose functional and therapeutic role remains to be elucidated in follow-up studies.
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Project description:This experiment was an aCGH study on 86 prostate tumors samples. The samples were profiled on Agilent Human Genome 44karrays to identify recurrent regions of deletion and amplification, thus revealing potential new tumor suppressor genes and/or oncogenes involved in prostate cancer. The CGH profile on the 44k arrays revealed a deletion at 5q21 in 17% of samples. CGH analysis of 86 prostate tumor samples.
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2009-02-01 | GSE10197 | GEO
Project description:The identification of lobular caricnoma in situ (LCIS) in a patient's specimen confers and appreciable increased risk of development of future invasive mammary carcinoma. However the study of LCIS presents a challenge as it is usually only recognized in fixed specimens and no good in vivo or in vitro models currently exist. Recent advances in high throughput genomics have made possible comprehensive copy number analysis of lesions such as this. We have characterized LCIS on microdissected cases of archival patient samples using aCGH. We used 4 cases of LCIS with adjacent ILC. Histological sections from 4 cases of LCIS and 4 cases of ILC microdissected, DNA extracted and subjected to whole genome amplification, and aCGH.
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