Project description:The use of Affymetrix U133 2.0 Plus chips on FFPE samples when coupled with a qPCR-based sample pre-assessment step, yielded satisfactory results from the point of view of biological reliability. When compared with the Illumina DASL WG platform, specifically designed for degraded RNA, the data generated with the Affymetrix platform showed a wider interquartile range (1.32 vs 0.57, p<2.2x10-16) suggesting a superior discriminatory power within samples as indicated by the good agreement with the immunohistiochemically derived ER status. FFPE primary breast cancer samples profiled using Illumina DASL WG platform after RNA amplification with the Nugen WT-Ovation FFPE System
Project description:The use of Affymetrix U133 2.0 Plus chips on FFPE samples when coupled with a qPCR-based sample pre-assessment step, yielded satisfactory results from the point of view of biological reliability. When compared with the Illumina DASL WG platform, specifically designed for degraded RNA, the data generated with the Affymetrix platform showed a wider interquartile range (1.32 vs 0.57, p<2.2x10-16) suggesting a superior discriminatory power within samples as indicated by the good agreement with the immunohistiochemically derived ER status. FFPE primary breast cancer samples profiled using Illumina DASL WG platform after RNA amplification with the Nugen WT-Ovation FFPE System The following criteria were considered for a direct comparison of 12 GEPs obtained from Affymetrix and DASL platforms: gene variability as defined by IQR, ESR1 expression in ER status subgroups defined by IHC, distribution of fold changes for predefined ER related genes when comparing ER positive and negative samples.
Project description:The use of Affymetrix U133 2.0 Plus chips on FFPE samples when coupled with a qPCR-based sample pre-assessment step, yielded satisfactory results from the point of view of biological reliability. When compared with the Illumina DASL WG platform, specifically designed for degraded RNA, the data generated with the Affymetrix platform showed a wider interquartile range (IQR 1.32 vs 0.57, p<2.2x10-16) suggesting a superior discriminatory power within samples as indicated by the good agreement with the immunohistiochemically derived ER status. FFPE primary breast cancer samples profiled using Affymetrix HG-U133 Plus 2.0 microarray platform after RNA amplification with the Nugen WT-Ovation FFPE System The following criteria were considered for a direct comparison of 12 GEPs obtained from Affymetrix and DASL platforms: gene variability as defined by IQR, ESR1 expression in ER status subgroups defined by IHC, distribution of fold changes for predefined ER related genes when comparing ER positive and negative samples.
Project description:Unluckily, FFPE archival methods lead to partial RNA degradation, limiting the amount of derivable information. This study aims to evaluate if the DASL gene expression assay, designed to generate reproducible data from degraded RNAs, is a reliable method to apply on RNA from FFPE tissues. In order to do that, we analyzed 20 FFPE breast cancer samples and 20 FF (Fresh Frozen) matched samples with the Illumina Whole Genome DASL platform for a genome-wide expression profiling.
Project description:The use of Affymetrix U133 2.0 Plus chips on FFPE samples when coupled with a qPCR-based sample pre-assessment step, yielded satisfactory results from the point of view of biological reliability. When compared with the Illumina DASL WG platform, specifically designed for degraded RNA, the data generated with the Affymetrix platform showed a wider interquartile range (IQR 1.32 vs 0.57, p<2.2x10-16) suggesting a superior discriminatory power within samples as indicated by the good agreement with the immunohistiochemically derived ER status.
Project description:Formalin-fixed, paraffin-embedded (FFPE) samples of varying grade (II-IV) malignant gliomas were measured by Illumina cDNA-mediated Annealing, Selection, extension and ligration (DASL) platform. DASL platform was selected for its specialized design for partially degraded RNA.
Project description:Triple negative breast tumours from archived formalin fixed paraffin embeded samples of the National Cancer Institute of Mexico were analyzed for differential gene expressión. Transcriptomic analysis of the 12 tumor samples was done with the FFPE-designed WG-DASL HT assay (Illumina) according to manufacturer’s instructions. This assay measures 29,285 annotated transcripts derived from the RefSeq database corresponding to 20,727 unique genes. Briefly, 200ng of total RNA were reverse-transcribed into biotinylated cDNA, which was then primer-extended with the Assay Specific Oligos. The cDNA was then amplified with universal primers and hybridized to Illumina Human WG DASL HT Expression BeadChip arrays. The Illumina Genome Studio V2010.2 was used to obtain the signal values (AVG-Signal), with no normalization and no background subtraction.The performance of hybridizations was evaluated by assessing the presence of outliers and the noise-to-signal ratios by calculating the ratio of centiles P95/P05 prior to normalisation for each sample. We defined outliers as samples with P95/P05 ratio <9.5. All samples were found to show a correct noise-to-signal ratio (P95/P05>9.6). For differential gene expression analysis, the public dataset GSE32124, which includes 33 fresh frozen tissue samples, generated on the Illumina HumanHT-12 v4.0 beadChip, and which contains 99.98% of the 29,285 probes of the Human WG DASL HT BeadChip was used as normal breast tissue control.
Project description:This SuperSeries is composed of the following subset Series: GSE32488: Expression profiling of formalin-fixed, paraffin-embedded (FFPE) breast cancer metastases of the lymph node and autopsy tissues [DASL HT-12 samples] GSE32489: Expression profiling of formalin-fixed, paraffin-embedded (FFPE) breast cancer metastases of the lymph node and autopsy tissues [DASL HumanRef-v3 samples] Refer to individual Series
Project description:Analysis of 97 formalin-fixed, paraffin-embedded (FFPE) primary breast tumors using Illumina DASL microarray technology on a Custom Breast Cancer Panel and the Illumina Human Cancer Panel. Molecular markers between the pathology defined subtypes of breast cancer were assessed to hypothesize potential therapeutic targets specific to the subtypes Molecular Characterization of 97 primary breast tumor formalin-fixed, paraffin-embedded (FFPE) specimens including 24 triple negative (TN: ER-, PR-, HER2-), 9 HER2-positive (HER2+: ER-, PR-, HER2+), and 64 hormone receptor-positive (HR+: ER+ and/or PR+). 91 of the 97 specimens were characterized on the Illumina Human Cancer DASL Panel and 86 of 97 specimens were characterized on a custom Breast Cancer DASL Panel, 80 of these specimens were common to both the Human Cancer DASL Panel and the custom Breast Cancer DASL Panel.
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.