ABSTRACT: Gene profiling using archival formalin-fixed paraffin-embedded breast cancer specimens can generate informative microarray data: A comparison with matched fresh fine needle aspiration biopsy samples (FFPE samples)
Project description:This SuperSeries is composed of the following subset Series: GSE23384: Gene profiling using archival formalin-fixed paraffin-embedded breast cancer specimens can generate informative microarray data: A comparison with matched fresh fine needle aspiration biopsy samples (FFPE samples) GSE23385: Gene profiling using archival formalin-fixed paraffin-embedded breast cancer specimens can generate informative microarray data: A comparison with matched fresh fine needle aspiration biopsy samples (FNA samples) Refer to individual Series
Project description:Formalin-fixed, paraffin-embedded (FFPE) tissues are an underused resource for molecular analyses. This proof of concept study aimed to compare RNAseq results from FFPE biopsies with the corresponding RNAlater® (Qiagen, Germany) stored samples from clear cell renal cell carcinoma (ccRCC) patients, to enable the decision of whether or not it is feasible to apply RNAseq technology to archival tissue. Core biopsies were obtained with a 16g needle from 16 patients undergoing partial or full nephrectomy. The RNA sequencing libraries were generated applying the new Illumina TruSeq® Access library preparation protocol.
Project description:Gene profiling using archival formalin-fixed paraffin-embedded breast cancer specimens can generate informative microarray data: A comparison with matched fresh fine needle aspiration biopsy samples (FNA samples)
Project description:This study aims to compare the potential of standard RNA-sequencing (RNA-Seq) and 3’ massive analysis of c-DNA ends (MACE) RNA-sequencing for the analysis of fresh tissue and describes transcriptome profiling of formalin-fixed paraffin-embedded (FFPE) archival human samples by MACE.
Project description:Renal epithelial neoplasms have characteristic chromosomal imbalances that can be used for classification. We have previously shown that virtual karyotypes (v-karyotype) derived from SNP microarrays can be performed on formalin-fixed paraffin embedded (FFPE) tissue samples but a direct comparison with karyotypes obtained by conventional cytogenetics has not been done. 20 archival FFPE tumor samples were analyzed with Affymetrix 10K 2.0 or 250K Nsp SNP microarrays.
Project description:Renal epithelial neoplasms have characteristic chromosomal imbalances that can be used for classification. We have previously shown that virtual karyotypes (v-karyotype) derived from SNP microarrays can be performed on formalin-fixed paraffin embedded (FFPE) tissue samples but a direct comparison with karyotypes obtained by conventional cytogenetics has not been done. 20 archival FFPE tumor samples were analyzed with Affymetrix 10K 2.0 or 250K Nsp SNP microarrays. 19 archival FFPE tumor samples were analyzed with Affymetrix 10K 2.0 or 250K Nsp SNP microarrays and virtual-karyotype results compared to those obtained by Cytogenetics.
Project description:Tissue sample acquisition is a limiting step in many studies. There are many thousands of formalin fixed paraffin embedded archival blocks collected around the world, but in contrast relatively few fresh frozen samples in tumor banks. Once samples are fixed in formalin the RNA is degraded and traditional methods for gene expression profiling are not suitable. In this study we have evaluated the whole genome DASL assay from Illumina to perform transcriptomic analysis from archived breast tumor tissue fixed in formalin paraffin embedded blocks. We profiled 76 familial breast tumors from cases carrying a BRCA1, BRCA2 or ATM mutation, or from non-BRCA1/2 families. We found that replicate samples correlated well with each other (r2=0.9-0.98). In 12/15 cases, the matched formalin-fixed and frozen samples predicted the same tumor molecular subtypes with confidence. These results demonstrate that the whole genome DASL assay is a valuable tool to profile degraded RNA from archival FFPE material. This assay will enable transcriptomic analysis of a large number of archival samples that are stored in pathology archives around the globe and consequently will have the potential to improve our understanding and characterisation of many diseases.
Project description:Profiling cellular heterogeneity in formalin-fixed paraffin-embedded (FFPE) tissues is key to characterizing clinical specimens for biomarkers, therapeutic targets, and drug responses. Here, we optimize methods for isolating intact nuclei and single nucleus RNA-seq from FFPE tissues in the mouse brain, and demonstrate a pilot application to a human clinical specimen of lung adenocarcinoma. Our method opens the way to broad applications of snRNA-Seq to archival tissues, including clinical samples.
Project description:Tissue sample acquisition is a limiting step in many studies. There are many thousands of formalin fixed paraffin embedded archival blocks collected around the world, but in contrast relatively few fresh frozen samples in tumor banks. Once samples are fixed in formalin the RNA is degraded and traditional methods for gene expression profiling are not suitable. In this study we have evaluated the whole genome DASL assay from Illumina to perform transcriptomic analysis from archived breast tumor tissue fixed in formalin paraffin embedded blocks. We profiled 76 familial breast tumors from cases carrying a BRCA1, BRCA2 or ATM mutation, or from non-BRCA1/2 families. We found that replicate samples correlated well with each other (r2=0.9-0.98). In 12/15 cases, the matched formalin-fixed and frozen samples predicted the same tumor molecular subtypes with confidence. These results demonstrate that the whole genome DASL assay is a valuable tool to profile degraded RNA from archival FFPE material. This assay will enable transcriptomic analysis of a large number of archival samples that are stored in pathology archives around the globe and consequently will have the potential to improve our understanding and characterisation of many diseases. RNA was extracted from FFPE Familial breast tumours and analysed using the WG-DASL assay for Illumina.
Project description:Archival formalin-fixed paraffin-embedded (FFPE) tissue samples hold a wealth of transcriptomic information; however, little is known about potential artifacts. Previously, we identified a consistent shift in global RNA-sequencing profiles between matching frozen and FFPE samples. We hypothesized that this shift was from fixing fresh tissue in formalin. To test this idea, RNA-sequencing was performed on liver samples collected from male mice treated with 600 ppm of a reference chemical (phenobarbital, 600 ppm phenobarbital) or vehicle control for 7 days. Samples were divided into: (1) fresh-frozen (FR); (2) directly fixed in 10% buffered formalin for 18 hours followed by paraffin embedding (FFPE); (3) frozen then fixed as FFPE (FR>FFPE); or (4) frozen then fixed in 70% ethanol followed by paraffin embedding (FR>OH) (n=6/group/condition). Direct fixation resulted in 2946 differentially expressed genes (DEGs), 98% of which were down-regulated. Freezing prior to fixation resulted in ≥95% fewer DEGs vs. FR, indicating that most formalin-derived transcriptional effects occurred with fixation. This was supported by follow-up studies, which identified consistent enrichment in oxidative stress, mitochondrial dysfunction, and transcription elongation pathways with formalin fixation. Notably, formalin fixation in the parent study did not significantly impact chemical response profiles, which were consistent with CAR/PXR activation and 600 ppm phenobarbital exposure. Our results demonstrate distinct transcriptional effects of formalin fixation that could impact gene expression studies using FFPE samples.
