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MicroRNA expression analysis in Uveal melanoma from formalin fixed paraffin embedded sections

ABSTRACT: miRNA expression analysis was done on Uveal melanoma, metastatic and non - metastatic case in formalin fixed paraffin embedded sections, identified from case registry and confirmed by Chromosome insitu hybridization harboring monosomy 3 aberration in metastaic case and no aberration in non metastatic case. 19 miRNAs were found to be expressed only in class I tumors (choroidal melanoma) and not in class II (liver metastasis) and 11 miRNAs were found to be expressed only in class II and not in class I. The tumors were found to harbor oncomirs in both choroidal melanoma and metastasizing melanoma targeting tumor suppressor genes and metastatic suppressor genes. None of the differentially expressed miRNAs in either case were found to be located on the chromosomes which have been proved to carry chromosomal abnormalities. Rather it was found that genes targeted by the miRNAs were found to be present in chromosomal regions that are often found to be deleted 8p22, 13q and 17p. Organism used: Homo sapiens. * Slides: Human miRNA V2 8x15k Arrays AMADID: 19118. * Starting material: 18 slides with formalin fixed Paraffin embedded sections-20 μm. * RNA Samples used: 225-94-DUP, 225-94-E, 727-07-DUP, 727-07 -E. * Labeling kit: Agilent miRNA labeling reagent and Hybridization Kit. * Labeling Method: Ligation of one cyanine3-pCp molecule to the 3' end of RNA molecule with greater than 90% efficiency that generates fluorescent miRNA. * Total RNA and cRNA Purification Kit: Biorad MicroBio Spin 6 columns. * Hybridization Kit: Agilent miRNA Hybridization kit. Hybridization protocol See Agilent Technologies website for miRNA microarray hybridization and wash protocol: http://www.chem.agilent.com/scripts/LiteraturePDF.asp?iWHID=50500 Scan protocol Laser detection of Cyanine 3 and Cyanine 5 fluorescence is performed using a confocal scanning instrument containing two tuned lasers, which excite Cyanine dyes at the appropriate wavelengths. Description Microarrays were scanned on an Agilent scanner (G2505C) at 100% PMT with 10% for lower intensity (XDR Scanning).Data extraction was carried out with Agilent Feature Extraction software (version 9.1), and normalization was done using linear per array algorithm according to the manufacturer’s protocol Data processing Feature extracted data was analyzed using GeneSpring GX v 10.0.2 software from Agilent. Normalization of the data was done in GeneSpring GX using the recommended Percentile shift normalization (50th percentile) . Further quality control of normalized data was done using correlation based condition tree to eliminate bad experiments. High expressed miRNA's were clustered using gene tree to identify significant gene expression patterns.

ORGANISM(S): Homo sapiens

SUBMITTER: Sivamani Sugandan

PROVIDER: S-ECPF-GEOD-17037 | biostudies-other |

REPOSITORIES: biostudies-other

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Project description:miRNA expression analysis was done on Uveal melanoma, metastatic and non - metastatic case in formalin fixed paraffin embedded sections, identified from case registry and confirmed by Chromosome insitu hybridization harboring monosomy 3 aberration in metastaic case and no aberration in non metastatic case. 19 miRNAs were found to be expressed only in class I tumors (choroidal melanoma) and not in class II (liver metastasis) and 11 miRNAs were found to be expressed only in class II and not in class I. The tumors were found to harbor oncomirs in both choroidal melanoma and metastasizing melanoma targeting tumor suppressor genes and metastatic suppressor genes. None of the differentially expressed miRNAs in either case were found to be located on the chromosomes which have been proved to carry chromosomal abnormalities. Rather it was found that genes targeted by the miRNAs were found to be present in chromosomal regions that are often found to be deleted 8p22, 13q and 17p. Organism used: Homo sapiens. * Slides: Human miRNA V2 8x15k Arrays AMADID: 19118. * Starting material: 18 slides with formalin fixed Paraffin embedded sections-20 μm. * RNA Samples used: 225-94-DUP, 225-94-E, 727-07-DUP, 727-07 -E. * Labeling kit: Agilent miRNA labeling reagent and Hybridization Kit. * Labeling Method: Ligation of one cyanine3-pCp molecule to the 3' end of RNA molecule with greater than 90% efficiency that generates fluorescent miRNA. * Total RNA and cRNA Purification Kit: Biorad MicroBio Spin 6 columns. * Hybridization Kit: Agilent miRNA Hybridization kit. Hybridization protocol See Agilent Technologies website for miRNA microarray hybridization and wash protocol: http://www.chem.agilent.com/scripts/LiteraturePDF.asp?iWHID=50500 Scan protocol Laser detection of Cyanine 3 and Cyanine 5 fluorescence is performed using a confocal scanning instrument containing two tuned lasers, which excite Cyanine dyes at the appropriate wavelengths. Description Microarrays were scanned on an Agilent scanner (G2505C) at 100% PMT with 10% for lower intensity (XDR Scanning).Data extraction was carried out with Agilent Feature Extraction software (version 9.1), and normalization was done using linear per array algorithm according to the manufacturer’s protocol Data processing Feature extracted data was analyzed using GeneSpring GX v 10.0.2 software from Agilent. Normalization of the data was done in GeneSpring GX using the recommended Percentile shift normalization (50th percentile) . Further quality control of normalized data was done using correlation based condition tree to eliminate bad experiments. High expressed miRNA's were clustered using gene tree to identify significant gene expression patterns.

Project description:We present a new concept, termed tissue lithography (TL), and its implementation which enables retrospective studies on formalin-fixed paraffin-embedded tissue sections. Tissue lithography uses a microfluidic probe to remove microscale areas of the paraffin layer on formalin-fixed paraffin-embedded biopsy samples. Current practices in sample utilization for research and diagnostics require complete deparaffinization of the sample prior to molecular testing. This imposes strong limitations in terms of the number of tests as well as the time when they can be performed on a single sample. Microscale dewaxing lifts these constraints by permitting deprotection of a fraction of a tissue for testing while keeping the remaining of the sample intact for future analysis. After testing, the sample can be sent back to storage instead of being discarded, as is done in standard workflows. We achieve this microscale dewaxing by hydrodynamically confining nanoliter volumes of xylene on top of the sample with a probe head. We demonstrate micrometer-scale, chromogenic and fluorescence-based immunohistochemistry against multiple biomarkers (p53, CD45, HER2 and β-actin) on tonsil and breast tissue sections and microarrays. We achieve stain patterns as small as 100 μm × 50 μm as well as multiplexed immunostaining within a single tissue microarray core with a 20-fold time reduction for local dewaxing as compared to standard protocols. We also demonstrate a 10-fold reduction in the rehydration time, leading to lower processing times between different stains. We further show the potential of TL for retrospective studies by sequentially dewaxing and staining four individual cores within the same tissue microarray over four consecutive days. By combining tissue lithography with the concept of micro-immunohistochemistry, we implement each step of the IHC protocol-dewaxing, rehydration and staining-with the same microfluidic probe head. Tissue lithography brings a new level of versatility and flexibility in sample processing and budgeting in biobanks, which may alleviate current sample limitations for retrospective studies in biomarker discovery and drug screening.

Project description:BackgroundWe have recently demonstrated that expression profiling is a more accurate and objective method to classify gliomas than histology. Similar to most expression profiling studies, our experiments were performed using fresh frozen (FF) glioma samples whereas most archival samples are fixed in formalin and embedded in paraffin (FFPE). Identification of the same, expression-based intrinsic subtypes in FFPE-stored samples would enable validation of the prognostic value of these subtypes on these archival samples. In this study, we have therefore determined whether the intrinsic subtypes identified using FF material can be reproduced in FFPE-stored samples.MethodsWe have performed expression profiling on 55 paired FF-FFPE glioma samples using HU133 plus 2.0 arrays (FF) and Exon 1.0 ST arrays (FFPE). The median time in paraffin of the FFPE samples was 14.1 years (range 6.6-26.4 years).ResultsIn general, the correlation between FF and FFPE expression in a single sample was poor. We then selected the most variable probe sets per gene (n=17,583), and of these, the 5000 most variable probe sets on FFPE expression profiles. This unsupervised selection resulted in a better concordance (R(2)=0.54) between expression of FF and FFPE samples. Importantly, this probe set selection resulted in a correct assignment of 87% of FFPE samples into one of seven intrinsic subtypes identified using FF samples. Assignment to the same molecular cluster as the paired FF tissue was not correlated to time in paraffin.ConclusionWe are the first to examine a large cohort of paired FF and FFPE samples. We show that expression data from FFPE material can be used to assign samples to intrinsic molecular subtypes identified using FF material. This assignment allows the use of archival material, including material derived from large-randomised clinical trials, to determine the predictive and/or prognostic value of 'intrinsic glioma subtypes' on Exon arrays. This would enable clinicians to provide patients with an objective and accurate diagnosis and prognosis, and a personalised treatment strategy.

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MicroRNA expression analysis in Uveal melanoma from formalin fixed paraffin embedded sections

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