Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1297695 | ENA |
REPOSITORIES: ENA
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Project description:BACKGROUND: Array Comparative Genomic Hybridization (aCGH) is a rapidly evolving technology that still lacks complete standardization. Yet, it is of great importance to obtain robust and reproducible data to enable meaningful multiple hybridization comparisons. Special difficulties arise when aCGH is performed on archival formalin-fixed, paraffin-embedded (FFPE) tissue due to its variable DNA quality. Recently, we have developed an effective DNA quality test that predicts suitability of archival samples for BAC aCGH. METHODS: In this report, we first used DNA from a cancer cell-line (SKBR3) to optimize the aCGH protocol for automated hybridization, and subsequently optimized and validated the procedure for FFPE breast cancer samples. We aimed for highest throughput, accuracy, and reproducibility applicable to FFPE samples, which can also be important in future diagnostic use. RESULTS: Our protocol of automated array-CGH on archival FFPE ULS-labeled DNA showed very similar results compared with published data and our previous manual hybridization method. CONCLUSION: This report combines automated aCGH on unamplified archival FFPE DNA using non-enzymatic ULS labeling, and describes an optimized protocol for this combination resulting in improved quality and reproducibility.
2007-02-23 | GSE7122 | GEO
Project description:BACKGROUND: Array Comparative Genomic Hybridization (aCGH) is a rapidly evolving technology that still lacks complete standardization. Yet, it is of great importance to obtain robust and reproducible data to enable meaningful multiple hybridization comparisons. Special difficulties arise when aCGH is performed on archival formalin-fixed, paraffin-embedded (FFPE) tissue due to its variable DNA quality. Recently, we have developed an effective DNA quality test that predicts suitability of archival samples for BAC aCGH. METHODS: In this report, we first used DNA from a cancer cell-line (SKBR3) to optimize the aCGH protocol for automated hybridization, and subsequently optimized and validated the procedure for FFPE breast cancer samples. We aimed for highest throughput, accuracy, and reproducibility applicable to FFPE samples, which can also be important in future diagnostic use. RESULTS: Our protocol of automated array-CGH on archival FFPE ULS-labeled DNA showed very similar results compared with published data and our previous manual hybridization method. CONCLUSION: This report combines automated aCGH on unamplified archival FFPE DNA using non-enzymatic ULS labeling, and describes an optimized protocol for this combination resulting in improved quality and reproducibility. In this study, we optimized the BAC araay-CGH protocol for automated hybridization for FFPE breast cancer samples. We have tested hybridization temperature and duration, different hybridization buffer conditions, and post-hybridization washing.
2010-06-12 | E-GEOD-7122 | biostudies-arrayexpress
Project description:In this study, the efficiency of four RNA extraction methods was compared on 23 FFPE cardiac tissue specimens. The Qiagen AllPrep DNA/RNA FFPE kit (Method QP), Qiagen AllPrep DNA/RNA FFPE kit, with protocol modification on the ethanol wash step after deparaffinization (Method QE), CELLDATA RNAstorm 2.0 FFPE RNA Extraction kit (Method BP) and CELLDATA RNAstorm 2.0 FFPE RNA Extraction Kit with protocol modifications on the lysis step (Method BL). In comparing RNA quality metrics across FFPE RNA extract, nucleic acids extracted with Method QE and QP had the highest RNA yield. However, Method QE outperformed Method QP as more extract from Method QE had DV 200 values above 30%. Both method BL and BP produced a similar range of RNA purity and yield but more extract from Method BL had DV 200 values above 30% compared to Method BP. When accessing distribution value, Method BL outperformed Methods BP, QE, and QP as more extracts from Method BL had DV 200 values above 30% (16/23 samples) compared to other methods (PDV200<0.001; Kruskal-Wallis). However, method QE outperformed other methods in terms of RNA yield. The sequencing performance of RNA extracts from Method QE and Method BL was further tested on 8 matching samples with high RNA yield and high DV200 value respectively. RNA extracts from Method QE which yielded the highest RNA quantity among all methods exhibited comparable sequencing performance to extract obtained through Method BL, which yielded extract with high DV200 value. This study suggests that the DV200 and RNA yield are both reliable pre-analytic metrics in determining a suitable method for successful transcriptome sequencing of FFPE samples and have important implications for future studies exploring transcriptome sequencing of FFPE cardiac specimens.
2024-05-23 | GSE267659 | GEO
Project description:DNA copy number changes with or without accompanying copy neutral changes such as unparental disomy (UPD) is a feature of the cancer genome that is linked to cancer development. However, technical problems with archived formalin-fixed, paraffin-embedded (FFPE) tissue samples have limited their general use in genomic profiling studies done using high-density single nucleotide polymorphism (SNP) microarray. To overcome the current problems with the use of this material in the detection of DNA copy number and copy neutral changes, we have devised two new protocols for extracting DNA from FFPE tissue. Genotyping efficiency and accuracy were improved using our novel protocols. After censoring the larger fragments, we obtained call rates for FFPE DNA equivalent to those for FF tissue DNA, with concordance rates between FFPE and FF tumor exceeding 99%. Identical DNA copy number changes were obtained for FFPE and FF; and between two new extraction protocols in tumor samples by using Affymetrix® high-density oligo-based SNP microarray platform. We observed UPD and recurrent gains and losses in tumor samples. Interestingly, we also identified UPD in the 5q and 13q regions in matching normal blood, FF adjacent breast tissue and tumor tissue in two samples. In conclusion, our new two DNA extraction protocols should substantially improve the ability to use archived material to help elucidate the complexity of early-stage breast cancer genomes. Keywords: SNP based array
2008-09-18 | GSE9154 | GEO
Project description:Formalin-fixed paraffin-embedded (FFPE) samples represent the gold standard for archiving pathology samples, and thus FFPE samples are a major resource of samples in clinical research. However, chromatin-based epigenetic assays in the clinical settings are limited to fresh or frozen samples, and are hampered by low chromatin yield in FFPE samples due to the lack of a reliable and efficient chromatin preparation method. Here, we introduce a new chromatin extraction method from FFPE tissues (Chrom-EX PE) for chromatin-based epigenetic assays.This study provided a new method that achieves efficient extraction of high-quality chromatin suitable for chromatin-based epigenetic assays with less damage on chromatin.
2019-03-18 | GSE128202 | GEO
Project description:In the study of tumor genetics, formalin-fixed paraffin-embedded (FFPE) tumors are the most readily available tissue samples. While DNA derived from FFPE tissue has been validated for array comparative genomic hybridization (aCGH) application, the suitability of such fragmented DNA for single-nucleotide polymorphism (SNP) array analysis has not been well examined. Furthermore, whole-genome amplification (WGA) has been used in the study of small precursor lesions to produce sufficient amount of DNA for aCGH analysis. It is unclear whether the same approach can be extended to SNP analysis. In this study, we examined the utility and limitations of genotyping platform performed on whole-genome amplified DNA from FFPE tumor samples for both copy number and SNP analyses. We analyzed the results obtained using DNA derived from matched FFPE and frozen tissue samples on Affymetrix 250K Nsp SNP array. Two widely used WGA methods, Qiagen (isothermal protocol) and Sigma (thermocycling protocol), were used to determine how WGA methods affect the results. We found that the use of DNA derived from FFPE tumors (without or with WGA) for high-resolution SNP array application can produce a significant amount of false positive and false negative findings. While some of these misinterpretations appear to cluster in genomic regions with high or low GC contents, the majority appears to occur randomly. Only large-scale chromosome LOH (>10Mb) can be reliably detected from FFPE tumor DNA samples (without or with WGA) but not smaller LOH or copy number alterations. Our findings here indicate a need for caution in SNP array data interpretation when using FFPE tumor-derived DNA, particularly with WGA.
2011-08-15 | GSE27399 | GEO
Project description:Laser-capture microdissection (LCM) allows the visualization and isolation of morphologically distinct subpopulations of cells from heterogeneous tissue specimens. In combination with formalin-fixed and paraffin-embedded (FFPE) tissue it provides a powerful tool for retrospective and clinically relevant studies of tissue proteins in a healthy and diseased context. In this study, we have developed an optimized protocol to facilitate efficient LCM analysis of FFPE tissue specimens. First, we optimized protein extraction from FFPE tissue by comparing different extraction buffers and investigating the influence of immunohistochemical and haematoxylin & eosin staining on proteins. SDS present in the protein extracts was removed with the SP3 digest method, which was modified to improve protein and peptide recoveries. Using a label-free approach protein expression of microdissected samples was compared to intact tissue sections from substantia nigra to evaluate the efficiency of LCM for the purification of small cell populations. The optimized protocol was used to analyse samples containing as few as ~3,000 cells isolated from the substantia nigra, using FFPE tissue. Replicate samples of 15 healthy donors were analysed in five separate TMT10plex batches, resulting in the quantification of >5,600 protein groups.
2020-03-05 | PXD016563 | Pride
Project description:Background and Aims: Liver proteomics with limited sample amounts is technically challenging but valuable for innovative hepatology research. We aimed to establish a simple and high-efficient approach for protein extraction and preparation from the formaldehyde-fixed paraffin-embedded (FFPE) liver samples for microproteomics assessment. Methods: Individual cell collected by laser capture microdissection (LCM) from FFPE liver slices were used as test samples with microscale samples of fresh-frozen liver or cultured liver cells as controls. Protocol for extracting protein was determined through the orthogonal test of 6 conditions of buffer compositions and heating processes. For sample preparation, we adjusted the protocol of single-tube solid-phase sample preparation (SP3) by enhancing protein precipitation and elution and developed a new method named HDMSP. HDMSP was then tested for its capability, reproducibility, and sample-type compatibility in analysis with nanoscale liquid chromatography-tandem mass spectrometry (nano LC-MS/MS). Results: For FFPE protein extraction, adding 4% SDS significantly increased the production by 2.5 times; incubation for 2 hours at 95℃ in alkaline amine buffer improved both the efficiency and quality of protein extraction. For the development of HDMSP, using 2% SDS to elute protein, using 70% acetonitrile but not ethanol, and increasing input of carboxyl magnetic beads to 2 mg/ml improved the rate of protein recovery by 88%, 50%, and 74%, respectively. For either 20 nL FFPE liver or HepG2 cell samples, or 1~2 μg fresh-frozen liver samples, the rate of protein recovery was stable at around 75%. LC-MS/MS demonstrated that the protocol designed for FFPE samples protein extraction allowed for unbiased extraction of insoluble or hydrophobic proteins and with HDMSP, the depth, identification, physicochemical properties, subcellular locations, and reproducibility of FFPE liver microproteome was comparable to those of fresh-frozen sample control. HDMSP also showed high efficiency and reproducibility for subcellular nuclear and cytoplasm-isolated proteins. Conclusion: The new approach including 300mM Tris, 4% SDS incubation for 2h at 95°C, and then preparation with HDMSP is simple, robust, and highly efficient for use in microproteomics of FFPE liver samples. This protocol can provide a solution reference for liver FFPE microproteomics.
2023-04-25 | PXD040010 |