Transcription profiling of human breast cancer samples kept at room temperature for different lengths of time before freezing
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Callari Maurizio
PROVIDER: S-ECPF-MEXP-2035 | biostudies-other |
REPOSITORIES: biostudies-other
Similar Datasets
Project description:In order to gain awareness of the gene expression artifacts linked to improper tissue handling also for this particular type of neoplasia, we have investigated gene expression profiles in a set of primary breast tumors, grossly subdivided into 4 aliquots and kept at room temperature for 0, 2, 6 and 24 hours after resection and before snap-freezing in liquid nitrogen.
2009-12-02 | E-MEXP-2035 | biostudies-arrayexpress
Project description:We find gene expression oscillations which arise after a time lag of around 7 hours.
2020-09-01 | GSE133421 | GEO
Project description:Gene expression profiles in Arabidopsis plants were compared between before and after of 37C treatment.
2007-02-21 | E-MEXP-602 | biostudies-arrayexpress
Project description:IntroductionMetabolic profiling of intact tumor tissue by high-resolution magic angle spinning (HR MAS) MR spectroscopy (MRS) provides important biological information possibly useful for clinical diagnosis and development of novel treatment strategies. However, generation of high-quality data requires that sample handling from surgical resection until analysis is performed using systematically validated procedures. In this study, we investigated the effect of postsurgical freezing delay time on global metabolic profiles and stability of individual metabolites in intact tumor tissue.Materials and methodsTumor tissue samples collected from two patient-derived breast cancer xenograft models (n = 3 for each model) were divided into pieces that were snap-frozen in liquid nitrogen at 0, 15, 30, 60, 90, and 120 min after surgical removal. In addition, one sample was analyzed immediately, representing the metabolic profile of fresh tissue exposed neither to liquid nitrogen nor to room temperature. We also evaluated the metabolic effect of prolonged spinning during the HR MAS experiments in biopsies from breast cancer patients (n = 14). All samples were analyzed by proton HR MAS MRS on a Bruker Avance DRX600 spectrometer, and changes in metabolic profiles were evaluated using multivariate analysis and linear mixed modeling.ResultsMultivariate analysis showed that the metabolic differences between the two breast cancer models were more prominent than variation caused by freezing delay time. No significant changes in levels of individual metabolites were observed in samples frozen within 30 min of resection. After this time point, levels of choline increased, whereas ascorbate, creatine, and glutathione (GS) levels decreased. Freezing had a significant effect on several metabolites but is an essential procedure for research and biobank purposes. Furthermore, four metabolites (glucose, glycine, glycerophosphocholine, and choline) were affected by prolonged HR MAS experiment time possibly caused by physical release of metabolites caused by spinning or due to structural degradation processes.ConclusionThe MR metabolic profiles of tumor samples are reproducible and robust to variation in postsurgical freezing delay up to 30 min.
| S-EPMC4730796 | biostudies-literature
Project description:Impact of pre-analytical handling on Bone Marrow (BM) mRNA Gene Expression: We have investigated the impact of RNA extraction protocols and time delays (24 and 48h) between sample aspiration and RNA extraction on RNA quality and gene expression profiles. Intact RNA can be extracted from BM samples stored at room temperature for up to 48h after aspiration. However, storage of BM has dramatic effects on mRNA expression of individual transcripts.
2007-07-28 | E-GEOD-1347 | biostudies-arrayexpress
Project description:Background: Glioblastomas are the most common primary brain tumour in adults. While the prognosis for patients is poor, gene expression profiling has detected signatures that can sub-classify GBMs relative to histopathology and clinical variables. One category of GBM defined by a gene expression signature is termed ProNeural (PN), and has substantially longer patient survival relative to other gene expression-based subtypes of GBMs. Age of onset is a major predictor of the length of patient survival where younger patients survive longer than older patients. The reason for this survival advantage has not been clear. We collected 267 GBM CEL files and normalized them relative to other microarrays of the same Affymetrix platform. 377 probesets on U133A and U133 Plus 2.0 arrays were used in a gene voting strategy with 177 probesets of matching genes on older U95Av2 arrays. Kaplan-Meier curves and Cox proportional hazard analyses were applied in distinguishing survival differences between expression subtypes and age. Results: Here we collected 267 glioblastomas and explore the relationship between gene expression subtype, age at diagnosis, and survival. This meta-analysis of published data in addition to new data confirms the existence of four distinct GBM expression-signatures. Further, patients with PN subtype GBMs had longer survival, as expected. However, the age of the patient at diagnosis is not predictive of survival time when controlled for the PN subtype. Conclusions: The survival benefit of younger age is nullified when patients are stratified by gene expression group. Thus, the main cause of the age effect in GBMs is the more frequent occurrence of PN GBMs in younger patients relative to older patients. Experiment Overall Design: Clinical data including histopathology, age, sex, and survival time from diagnosis were retrieved from 181 glioblastomas which have been reported within previous studies between 2003 and 2006 and for which CEL files (Affymetrix, Santa Clara, CA) were available from the authors. In addition, we collected 86 new patient-unique tumour biopsies from the UCLA Neuro-oncology Program (n = 55) and the Barrow Neurological Institute (n = 31) for a grand total of 267 glioblastomas. Newly acquired tumours were collected through institutional review board approved protocols and assigned WHO grades at UCLA Neuropathology or Barrow Neuropathology by PSM. Time of survival (days), sex, and, age were collected where available. Patient age at the time of diagnosis was available for 239 patients and ranged from 18 to 86 years. Sex of the individual was available for those 239 patients (151 males and 88 females). There were no technical replicates. There were no control or reference samples. No dye swap due to single channel array platforms.
| S-ECPF-GEOD-13041 | biostudies-other
Project description:Meningiomas are typically considered a benign tumor that can be cured by complete surgical resection; however, a percentage of patients have recurrent disease, even after apparently complete resections. These patients require additional surgeries, radiation therapy, chemotherapy, or a combination of all three. The ability to recognize these patients prior to recurrence would promote earlier use of adjuvant therapy, thus improving overall patient outcome. Unfortunately, identification of meningiomas with this more aggressive phenotype is difficult, and standard histopathological techniques rarely suffice. The identification of genetic and molecular parameters that can help to define these more aggressive tumors would improve prognostication and treatment planning for patients with meningiomas. 1. Establish gene profiles for benign (grade 1) and aggressive (grades 2 and 3) meningiomas. 2. Determine if there are particular expression profiles that can help differentiate between benign and aggressive meningiomas. 3. Determine if there is/are specific gene(s) whose expression is/are altered in benign vs aggressive tumors. 4. Determine if there is a correlation between specific genetic abnormalities in these tumors (as analyzed by fluorescent in situ hybridization; FISH) and gene expression profiles. Our overall hypothesis is that there are molecular and biochemical changes that can be used to identify meningiomas that will have a more aggressive clinical course. Specific Aims 1 and 2: RNA from flash frozen or RNA-later preserved tissue (from all three grades of meningiomas) has been used for RNA isolation using standard protocols. RNA quantity has been determined using a RiboGreen RNA quantitation Kit (Molecular Probes), and RNA quality has been demonstrated using standard formaldehyde gels. These samples will be sent to the NINDS/NIMH microarray consortium for Affymetrix microarray analyses. Data analysis will be done using GeneSpring software (Silicon Genetics, Inc.) with assistance from consortium personnel. Specific Aim 3: Differentially expressed genes identified through microarray analyses will be analyzed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Real time qRT-PCR is a standard technique used in our laboratory for gene expression analysis. Specific Aim 4: FISH analyses of paraffin-embedded tissue has been completed for 77 tumors. We have frozen tissue from a number of these patients. RNA from these samples will be used for microarray analyses (Specific Aims 1-3). The results of Speicifc Aims 1 and 2 will affect how we perform our correlation analyses. This will be done with the assistance of contracted statistical personnel
| S-ECPF-GEOD-4780 | biostudies-other
Project description:Microarray analyses comparing the transcriptional profile of wild-type EGDe relative to ∆lmo0688 (L. monocytogenes) during standing growth at RT in BHI broth. These analyses revealed that Lmo0688 is required for expression of flagellar motility genes during growth at RT. In this study, we identify an additional component of the molecular circuitry governing temperature-dependent flagellar gene expression. At low temperatures (30˚C and below), MogR repression activity is specifically inhibited by an anti-repressor, GmaR. We demonstrate that GmaR forms a stable complex with MogR, preventing MogR from binding its DNA target sites. GmaR anti-repression activity is temperature-dependent due to DegU-dependent transcriptional activation of gmaR at low temperatures. Thus, GmaR production represents the first committed step for flagella production in L. monocytogenes. Interestingly, GmaR also functions as a glycosyltransferase exhibiting O-linked N-acetylglucosamine transferase (OGT) activity for flagellin (FlaA). GmaR is the first OGT to be identified and characterized in prokaryotes. Unlike the well-characterized, highly conserved OGT regulatory protein in eukaryotes, the catalytic activity of GmaR is functionally separable from its anti-repression function. Keywords: EGDe vs ∆688, Temperature, Growth condition
2006-10-31 | GSE6032 | GEO
Project description:mRNA expression data were collected from patients with brain tumor to improve diagnostic of gliomas on molecular level.
| S-ECPF-GEOD-4290 | biostudies-other
Project description:We measured baseline gene expression profiles for a set of breast tumors. Note: this experiment was modified in June 2008 when the CEL files associated with some hybridizations were changed.
| S-ECPF-TABM-158 | biostudies-other