{"owner": "ArrayExpress Uploader", "pop_total": 0, "id": 9648, "factors": [{"GSM589506 1": {"TISSUE": "universal reference"}}, {"GSM589507 1": {"TISSUE": "universal reference"}}, {"GSM589508 1": {"TISSUE": "universal reference"}}, {"GSM589509 1": {"TISSUE": "brain reference"}}, {"GSM589510 1": {"TISSUE": "brain reference"}}, {"GSM589511 1": {"TISSUE": "brain reference"}}], "ownerprofile_id": "arrayexpress_sid", "platform": 3, "summary_wrapped": "The Affymetrix GeneChip\u00ae system is a commonly used platform for microarray analysis but the technology is inherently expensive....", "pubmed_id": 20946593, "geo_gse_id": "E-GEOD-23906", "owner_profile": "/profile/8773/arrayexpressuploader", "factor_count": 0, "sample_count": 6, "tags": ["brain"], "lastmodified": "Jan.17, 2015", "is_default": false, "geo_gds_id": "", "slug": "evaluation-of-gene-expression-data-generated-from", "geo_id_plat": "E-GEOD-23906_A-AFFY-33", "name": "Evaluation of gene expression data generated from expired Affymetrix GeneChip\u00ae microarrays using MAQC reference RNA samples", "created": "Jan.17, 2015", "summary": "The Affymetrix GeneChip\u00ae system is a commonly used platform for microarray analysis but the technology is inherently expensive. Unfortunately, changes in experimental planning and execution, such as the unavailability of previously anticipated samples or a shift in research focus, may render significant numbers of pre-purchased GeneChip\u00ae microarrays unprocessed before their manufacturer\u2019s expiration dates. Researchers and microarray core facilities wonder whether expired microarrays are still useful for gene expression analysis. Our results demonstrated that microarray data generated using U133A microarrays, which were more than four years past the manufacturer\u2019s expiration date, were highly specific and consistent with those from unexpired microarrays in identifying DEGs despite some appreciable fold change compression and decrease in sensitivity. Our data also suggested that the MAQC reference RNA samples, stored at -80\u00b0C, were stable over a time frame of at least four years. The new gene expression data were generated with 12 microarrays (2 types of microarrays \u00d7 2 samples \u00d7 3 replicates). Three replicates for each of the two MAQC samples (A = Stratagene\u2019s Universal Human Reference RNA; B = Ambion\u2019s Human Brain Reference RNA) were profiled in 2009 by using both the expired U133A microarrays (expired in 2004) and the unexpired U133Plus2 microarrays. In addition, gene expression data generated with unexpired U133Plus2 microarrays (AFX), other microarray platforms, and TaqMan\u00ae assays by the MAQC project in 2005 were used as references to assess the stability of the MAQC samples stored at -80\u00b0C for four years by comparing new microarray data with those obtained four years ago. The MAQC reference data also allowed for further evaluation of the usefulness of the data generated with expired U133A microarrays.", "source": "http://www.ebi.ac.uk/arrayexpress/experiments/E-GEOD-23906", "species": "human", "sample_source": "http://www.ebi.ac.uk/arrayexpress/experiments/E-GEOD-23906/samples/"}