Project description:A study to evaluate techniques for repairing DNA from formalin-fixed paraffin-embedded (FFPE) tissue samples by direct comparison of FFPE DNA repair methods prior to analysis on genome-wide methylation array to matched fresh frozen (FF) tissues.
Project description:A study to evaluate techniques for repairing DNA from formalin-fixed paraffin-embedded (FFPE) tissue samples by direct comparison of FFPE DNA repair methods prior to analysis on genome-wide methylation array to matched fresh frozen (FF) tissues. Formalin-fixed paraffin-embedded tissue from three colon adenocarcinoma samples were subjected to different FFPE-oriented DNA repair approaches and sequences, then compared with corresponding fresh frozen tissues. All samples were hybridized to the Illumina Infinium 450k Human Methylation BeadChip.
Project description:MicroRNAs (miRNAs) are small non-coding RNAs that repress gene expression at the post transcriptional level via an antisense RNA-RNA interaction. Generally, miRNAs derived from snap frozen or fresh samples are used for array based profiling. Since tissues in most pathology departments are available only in formalin fixed and paraffin embedded state, we sought to evaluate the miRNA derived from formalin fixed and paraffin embedded (FFPE) samples for microarray analysis. In this study, miRNAs extracted from matched snap frozen and FFPE samples were profiled using the Agilent miRNA array platform. Each miRNA sample was hybridized to arrays containing probes interrogating 470 human miRNAs. A total of seven cases were compared in either duplicate or triplicate. Intrachip and interchip analyses demonstrated that the processes of miRNA extraction, labeling and hybridization from both frozen and FFPE samples are highly reproducible and add little variation to the results, as technical replicates showed high correlations (Kendall tau=0.722-0.853, Spearman rank correlation coefficient=0.891-0.954). Our results showed consistent high correlation between matched frozen and FFPE samples (Kendall tau=0.669-0.815, Spearman rank correlation coefficient=0.847-0.948), supporting the use of FFPE-derived miRNAs for profiling. Keywords: formalin-fixed and paraffin-embedded (FFPE) miRNA profiling
Project description:Genome-wide DNA methylation screening was performed using the Infinium MethylationEPIC BeadChip in 49 fresh-frozen tissue samples and 31 formalin-fixed paraffin-embedded tissue samples obtained from surgically resected materials of patients with endometrioid endometrial cancer.
Project description:Defining the tumor immune microenvironment (TIME) of patients using transcriptome analysis is gaining more popularity. Here, we examined and discussed the pros and cons of using RNA -sequencing for Fresh Frozen (FF) samples and targeted gene expression immune profiles (NanoString) for Formalin-Fixed, Paraffin-Embedded (FFPE) samples to characterize the TIME of ependymoma samples.
Project description:To investigate the microRNA profiles of ovarian clear cell carcinoma (OCCC), microRNA sequencing was performed using formalin-fixed, paraffin-embedded (FFPE) and fresh-frozen clinical samples. Moreover, patient-derived xenograft (PDX) tumors and cell lines were also investigated.
Project description:Furan is a mouse and rat hepatocarcinogen. We sought to determine if furan-induced gene expression changes could be detected in paired fresh-frozen and formalin-fixed paraffin embedded (FFPE) samples using one-colour microarrays. All samples in this study (fresh-frozen, 18 hours in formalin, 3 weeks in formalin) were also examined using two-colour microarrays and RNA-seq (ribo-depletion and polyA-enrichment protocols) in order to determine the effect of the technology on gene expression profiles.
Project description:Abstract: Sufficient quantity of genomic DNA can be a bottleneck in genome-wide analysis of clinical tissue samples. DNA polymerase Phi29 can be used for the random-primed amplification of whole genomes, although the amplification may introduce bias in gene dosage. We have performed a detailed investigation of this technique in archival fresh-frozen and formalin-fixed/paraffin-embedded tumor DNA by using cDNA microarray-based comparative genomic hybridization. Phi29 amplified DNA from matched pairs of fresh-frozen and formalin-fixed/paraffin-embedded tumor samples with similar efficiency. The distortion in gene dosage representation in the amplified DNA was nonrandom and reproducibly involved distinct genomic loci. Regional amplification efficiency was significantly linked to regional GC content of the template genome. The biased gene representation in amplified tumor DNA could be effectively normalized by using amplified reference DNA. Our data suggest that genome-wide gene dosage alterations in clinical tumor samples can be reliably assessed from a few hundred tumor cells. Therefore, this amplification method should lend itself to high-throughput genetic analyses of limited sources of tumor, such as fine-needle biopsies, laser-microdissected tissue, and small paraffin-embedded specimens. This SuperSeries is composed of the SubSeries listed below.