Reliable single cell array CGH for clinical samples
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE52366 | GEO | 2014/01/21
SECONDARY ACCESSION(S): PRJNA227506
REPOSITORIES: GEO
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Project description:Establishment and subsequent validation of a aCGH protocol for WGA (whole genome amplification) products originating from single cell or low amount of starting material (i.e. microdissected FFPE tissue samples). The establishment of the protocol involved testing of three DNA labeling protocols. Two labeling protocols were designed specifically for Ampli1(TM) WGA products. Additionally random primed isothermal (Klenow-based) labeling approach was tested (MM-CM-6hlendick et al., PLoS One. 2013 Jun 25;8(6):e67031.). In addition two different types of reference samples were tested and reference based on single-cell WGA products was chosen as most suitable in the end. The validation of the protocol assessed the following aspects: (1) performance of the protocol on primary and reamplified WGA products, (2) accuracy of the protocol in term of sensitivity of the CNA detection, (3) accuracy in terms of recapitulation of complex patterns of CNAs, (4) accuracy in terms of quantitative assessment of the CNAs, (5) ability to detect genomic heterogeneity of single cells (obtained either from in vitro cultures or from clinical patient material), (6) ability to detect minimal regions of aberration within a panel of disseminated cancer cells and corresponding tumor tissues. Establishment and validation of the single-cell aCGH protocol: two condition experiment (i.e. PCR-based labeling technique 1 vs. PCR-based labeling technique 2; PCR-based labeling technique 2 vs. random-primed isothermal (Klenow) labeling approach; reference DNA from cell pool WGA product vs. reference DNA from single-cell WGA products). Validation of the protocol: comparison of the CNA profiles between single-cell WGA products and corresponding bulk DNA. Analysis of the DCC and corresponding FFPE tumor tissue samples: single-condition experiment performed on samples collected at different stages of the disease (DCCs from bone marrow) and/or from different sites (primary tumor-breast; metastasis-lymph nodes; DCCs-bone marrow). Microarray data is corresponding data depicted in the paper manuscript titled: Reliable single cell array CGH for clinical samples
2014-01-21 | E-GEOD-52366 | biostudies-arrayexpress
Project description:Methods of comprehensive microarray based analyses of single cell DNA are rapidly emerging. Whole genome amplification (WGA) remains a critical component for these methods to be successful. A number of commercially available WGA kits have been independently utilized in previous single cell microarray studies. However, direct comparison of their performance on single cells has not been conducted. The present study demonstrates that among previously published methods, a single cell GenomePlex WGA protocol provides the best combination of speed and accuracy for SNP microarray based copy number analysis when compared to a REPLI-g or GenomiPhi based protocol. Alternatively, for applications that do not have constraints on turn-around time and that are directed at accurate genotyping rather than copy number assignments, a REPLI-g based protocol may provide the best solution.
2010-12-20 | GSE24690 | GEO
Project description:In the study of tumor genetics, formalin-fixed paraffin-embedded (FFPE) tumors are the most readily available tissue samples. While DNA derived from FFPE tissue has been validated for array comparative genomic hybridization (aCGH) application, the suitability of such fragmented DNA for single-nucleotide polymorphism (SNP) array analysis has not been well examined. Furthermore, whole-genome amplification (WGA) has been used in the study of small precursor lesions to produce sufficient amount of DNA for aCGH analysis. It is unclear whether the same approach can be extended to SNP analysis. In this study, we examined the utility and limitations of genotyping platform performed on whole-genome amplified DNA from FFPE tumor samples for both copy number and SNP analyses. We analyzed the results obtained using DNA derived from matched FFPE and frozen tissue samples on Affymetrix 250K Nsp SNP array. Two widely used WGA methods, Qiagen (isothermal protocol) and Sigma (thermocycling protocol), were used to determine how WGA methods affect the results. We found that the use of DNA derived from FFPE tumors (without or with WGA) for high-resolution SNP array application can produce a significant amount of false positive and false negative findings. While some of these misinterpretations appear to cluster in genomic regions with high or low GC contents, the majority appears to occur randomly. Only large-scale chromosome LOH (>10Mb) can be reliably detected from FFPE tumor DNA samples (without or with WGA) but not smaller LOH or copy number alterations. Our findings here indicate a need for caution in SNP array data interpretation when using FFPE tumor-derived DNA, particularly with WGA. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted from cryopreserved and FFPE mesenchymal tumor samples without or with WGA, as well as genomic snap-frozen non-neoplastic tissue DNA from 5 adult individuals to serve as reference DNA. WGA was performed using the REPLI-g® FFPE kit (Qiagen, Valencia, CA, USA) and GenomePlex® Tissue Whole Genome Amplification WGA5 kit (Sigma, Saint Louis, MO, USA) in parallel in accordance with the manufacturers’ protocols. A two- to eight-hour individualized reaction time was used in the Qiagen platform for each sample. A gradient amount of initial DNA (10ng, 30ng, 60ng, 100ng and 150ng) was tested followed by gel electrophoresis and qualitative multiplex PCR assay to determine the quality of post-WGA products. At least four independent experiments were concurrently performed per template amplification. Four separateWGA reaction products were pooled for each sample for subsequent microarray analysis to minimize the amplification bias and allele dropout. One of the Affymetrix GeneChip® Human Mapping 500K Array Set (Nsp 250K SNP array) was used for genotyping analysis. Four gastrointestinal stromal tumors with known cytogenetic aberrations were included. Two cases were sucessfullly amplified and passed the quality tests. A total of 12 samples were compared between each other, including frozen tissue DNA (as reference), frozen tissue DNA with WGA (two platforms), FFPE tissue DNA, and FFPE tissue DNA with WGA (two platforms) from each case.
2011-08-14 | E-GEOD-27399 | biostudies-arrayexpress
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
Project description:We have developed a total RNA amplification and labeling strategy for use with Affymetrix GeneChips. Our protocol, which we denote BIIB, employs two rounds of linear T7 amplification followed by Klenow labeling to generate a biotinylated cDNA. In benchmarking studies using a titration of mouse universal total RNA, BIIB outperformed commercially available kits in terms of sensitivity, accuracy, and amplified target length, while providing equivalent results for technical reproducibility. BIIB maintained 50 and 44% present calls from 100 and 50 pg of total RNA, respectively. Inter- and intrasample precision studies indicated that BIIB produces an unbiased and complete expression profile within a range of 5 ng to 50 pg of starting total RNA. From a panel of spiked exogenous transcripts, we established the BIIB linear detection limit to be 20 absolute copies. Additionally, we demonstrate that BIIB is sensitive enough to detect the stochastic events inherent in a highly diluted sample. Using RNA isolated from whole tissues, we further validated BIIB accuracy and precision by comparison of 224 expression ratios generated by quantitative real-time PCR. The utility of our method is ultimately illustrated by the detection of biologically expected trends in a T cell/B cell titration of 100 primary cells flow sorted from a healthy mouse spleen. Keywords: Development and validation of an amplification and labeling protocol for transcriptional profiling on Affymetrix GeneChips, cDNA target on Affymetrix Genechip, small or limiting total RNA samples
2006-06-23 | GSE5130 | GEO
Project description:We have developed a total RNA amplification and labeling strategy for use with Affymetrix GeneChips. Our protocol, which we denote BIIB, employs two rounds of linear T7 amplification followed by Klenow labeling to generate a biotinylated cDNA. In benchmarking studies using a titration of mouse universal total RNA, BIIB outperformed commercially available kits in terms of sensitivity, accuracy, and amplified target length, while providing equivalent results for technical reproducibility. BIIB maintained 50 and 44% present calls from 100 and 50 pg of total RNA, respectively. Inter- and intrasample precision studies indicated that BIIB produces an unbiased and complete expression profile within a range of 5 ng to 50 pg of starting total RNA. From a panel of spiked exogenous transcripts, we established the BIIB linear detection limit to be 20 absolute copies. Additionally, we demonstrate that BIIB is sensitive enough to detect the stochastic events inherent in a highly diluted sample. Using RNA isolated from whole tissues, we further validated BIIB accuracy and precision by comparison of 224 expression ratios generated by quantitative real-time PCR. The utility of our method is ultimately illustrated by the detection of biologically expected trends in a T cell/B cell titration of 100 primary cells flow sorted from a healthy mouse spleen. Experiment Overall Design: Various experimental designs were used as part of the validation process for this total RNA amplification and labeling protocol. 103 samples were analyzed on Affymetrix GeneChips as part of this GEO series. Details of the BIIB protocol and supporting experiments are published in Genomics. 2006 Jul;88(1):111-21
2008-06-13 | E-GEOD-5130 | biostudies-arrayexpress
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2009-01-13 | E-GEOD-13496 | biostudies-arrayexpress
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2014-03-01 | E-MTAB-2340 | biostudies-arrayexpress
Project description:Methods of comprehensive microarray based analyses of single cell DNA are rapidly emerging. Whole genome amplification (WGA) remains a critical component for these methods to be successful. A number of commercially available WGA kits have been independently utilized in previous single cell microarray studies. However, direct comparison of their performance on single cells has not been conducted. The present study demonstrates that among previously published methods, a single cell GenomePlex WGA protocol provides the best combination of speed and accuracy for SNP microarray based copy number analysis when compared to a REPLI-g or GenomiPhi based protocol. Alternatively, for applications that do not have constraints on turn-around time and that are directed at accurate genotyping rather than copy number assignments, a REPLI-g based protocol may provide the best solution. Affymetrix SNP arrays were processed according to the manufacturer's directions on DNA extracted from human fibroblast cell lines and single fibroblast cells. Afflymetrix SNP array analysis was successfully completed on 46 lymphocyte single cell samples, 8 gDNA extracted from cell lines, 11 reference gDNA extracted from cell lines and 3 reference gDNA samples from the RMA of New Jersey DNA bank. GSM617116 to GSM617129: CEL files were processed using GTYPE version 4 (Affymetrix Inc., Genotyping Console 4.0 Manual) using the DM algorithm for genotype calls. Copy number and loss of heterozygosity were calculated from CHP files using CNAT version 4.1 (Affymetrix Inc., Genotyping Console 4.0 Manual) analysis against a reference set consisting of three normal females from in house gDNA bank, 11 normal females from Coriel cell lines and 16 normal females from the HapMap database (www.hapmap.org). The 16 normal females are NA10855, NA10863, NA11832, NA12057, NA12234, NA12717, NA12813, NA18505, NA18508, NA18517, NA19137, NA19152, NE00088, NE00091, NE00403, and NE01119.
2010-12-20 | E-GEOD-24690 | biostudies-arrayexpress