Project description:Comparison between in vitro transcription- and cDNA-mediated annealing, selection and ligation (DASL)-based assays on brain-specific reference RNA, and postmortem frozen and formalin fixed brain tissue from autistic and control cases. Investigation of data preprocessing techniques for DASL-assayed RNA samples from frozen brain tissue.
Project description:Comparison between in vitro transcription- and cDNA-mediated annealing, selection and ligation (DASL)-based assays on brain-specific reference RNA, and postmortem frozen and formalin fixed brain tissue from autistic and control cases. Investigation of data preprocessing techniques for DASL-assayed RNA samples from frozen brain tissue. IVT- and DASL-based expression assays were performed on 10 reference RNA samples (brain and pooled artificially degraded at 0, 10, 30, and 60 min), 4 formalin-fixed tissue-extracted RNA samples with replicates, and 57 frozen tissue-extracted RNA samples with replicates. A subset of the 57 (N=33 samples) from frozen brain tissue assayed using the DASL-based platform were then used to test different dataset preprocessing strategies implemented in the lumi package in R/Bioconductor. The data from frozen-tissue extracted DASL-processed RNA samples passing exclusion criteria were log2 transformed and normalized using quantile normalisation with lumi in R (quantile-normalized data available as a supplementary file linked to the Series record).
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:FIN-Seq is a method that allows transcriptional profiling of specific cell types in frozen postmortem human CNS tissues. Briefly, nuclei from frozen CNS samples are isolated, fixed, and immunolabeled with antibodies for prospective isolation. The RNA from the FACS isolated nuclei are extracted and an RNA sequencing library is generated for subsequent sequencing.
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: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:We performed RNA-Seq for the corpus callosum sampled from 12 individuals. The samples were dissected from the frozen postmortem brain. The 12 individuals were matched by their age, sex and ethnicity for the postmortem brain samples, but differed in their disease status with half of the subjects were diagnosed with autism spectrum disorders.
Project description:We performed RNA-Seq for the BA9/40/AMY for a typically developing individual #5407. The samples were dissected from the frozen postmortem brain.
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:Formalin-fixed paraffin-embedded (FFPE) samples are a highly desirable resource for epigenetic studies, but there is no suitable platform to assay genome-wide methylation in these widely available resources. Recently, Thirwell et al. (2010) have reported a modified ligation-based DNA repair protocol to prepare FFPE DNA for the Infinium methylation assay. In this study, we have tested the accuracy of methylation data obtained with this modification by comparing paired fresh-frozen (FF) and FFPE colon tissue from colorectal cancer patients. We report locus-specific correlation and concordance of tumor-specific differentially-methylated loci (DML), both of which were not previously assessed.
