Array comparative genomic hybridization of Canine Oral Melanoma (COM) archival samples.
Ontology highlight
ABSTRACT:
ORGANISM(S): Canis lupus familiaris
PROVIDER: GSE131923 | GEO | 2020/01/13
REPOSITORIES: GEO
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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: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.
2020-09-08 | GSE148174 | 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:Soft tissue sarcomas (STS) often present a significant diagnostic challenge as many STS bear histologic resemblance, but are known to have very different clinical and biologic characteristics. Some STS subtypes are characterized by specific genetic abnormalities and this has helped in their classification, diagnosis and even treatment. However, a large majority of STS have no known specific genetic aberrations even though they almost always have highly aberrant karyotypes. We therefore hypothesize that the latter subgroup of STS bear genetic abnormalities that are sub-type specific, but as yet unidentified. High-resolution mapping of copy number aberrations in cancer genomes is a valuable way of identifying recurrent genomic changes that could be of pathogenetic significance. Traditionally, this has been done using high quality DNA obtained from fresh frozen tissue or cells and archived tissue is generally regarded as unsuitable because of the degradative effects of formalin fixation on DNA. Utility of archival tumour material for such molecular genetic analysis is vital, especially for rare cancers like STS but recent efforts to accomplish this have produced variable results. We therefore set out, in addition to optimize a protocol for obtaining genomic copy number data from formalin-fixed, paraffin-embedded (FFPE) STS material that is comparable to that from fresh frozen (FF) material. Microarray-based Comparative Genomic Hybridization (aCGH), a high- resolution, genome-wide method was used to identify somatic copy number aberrations (SCNAs) in primary STS samples (fresh frozen and archival FFPE), using an optimized protocol for labeling DNA. Findings were confirmed using Conventional Cytogenetics and Fluorescence in-situ Hybridization (FISH). Data obtained from paired samples (FF and FFPE) of the same tumours showed similar results and array results were consistently of good quality. On-going analysis of the recurrent SCNAs in combination with expression data and clinical correlates may serve to identify specific patterns that can serve as diagnostic markers, characterize subgroups with prognostic implication or identify potential therapeutic targets. To identify common CNAs among LMS fresh and FFPE. 25 samples in total: 22 individual FFPE cases; 3 cases also obtained fresh. Reference DNA was obtained from same patient when possible, otherwise commercial genomic DNA was used [Promega® UK with Cat Nos. G1471 (male) and G1521 (female)].
2015-07-24 | E-GEOD-39663 | biostudies-arrayexpress
Project description:Array comparative genomic hybridization of Canine Oral Melanoma (COM) archival samples.
| PRJNA545326 | ENA
Project description:We investigated a cohort of 34 archival cutaneous melanoma samples by Agilent 40 kb-resolution CGH array. We found a non-random distribution of precise CNAs predictive for clinical outcome. Although most of the alterations defined in this study have been already reported, we mapped novel melanoma-specific CNAs at highest accuracy. Moreover, our data revealed distinct amplifications hotspots, some of which were validated by quantitative real-time PCR, enabling the identification of novel melanoma oncogenic candidates. Keywords: Cutaneous melanoma, Copy number alterations, Biomarkers, FFPE We examined 34 primary melanoma formalin-fixed and paraffin-embedded (FFPE) samples by using array comparative genomic hybridization (aCGH) for DNA copy number alterations (CNAs). Genomic DNA was extracted, referred to a sex-matched diploid commercial control DNA (Promega Corporation, Madison, WI, cat. G1417 and G1521), and hybridized on the Agilent SurePrint G3 Human CGH Microarray 8x60k, cat. G4827A.
2013-07-01 | E-GEOD-45354 | biostudies-arrayexpress
Project description:The aim of this work was to identify the copy number aberrations (CNAs) by high-resolution array comparative genomic hybridization (aCGH) on 7 dogs with newly diagnosed FL and 5 dogs with newly diagnosed MZL.
2020-06-30 | GSE131618 | GEO
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
2011-06-22 | E-GEOD-23386 | biostudies-arrayexpress
Project description:Purpose: Only a limited number of genetic studies have been performed in primary central nervous system lymphomas (PCNSL), partly due to the rarity of the tumors and the very limited amount of available tissue. In this report, we present the first molecular characterization of copy-number abnormalities (CNA) of newly diagnosed PCNSL by array-based comparative genomic hybridization in formalin fixed paraffin embedded (FFPE) specimens and compare the results with matched frozen tumor specimens. Experimental design: We performed array-based comparative genomic hybridization (aCGH) in FFPE tissues from PCNSL. Results were compared with matched paired frozen tumors. Results: Our analysis confirmed the good to fair quality and reliability of the data generated from limited amounts of tumoral FFPE tissue. Overall, all PCNSL cases were characterized by highly complex karyotypes with a median of 23 copy-number abnormalities (CNA) per patient (range 17-47). Overall, 20 chromosomal regions were recurrently found in more than 40% of cases. Deletions of 6p21, 6q, 9p21.3 and gain of 12q12-q24.33 were the commonest CNA. Other minimal affected regions were defined, and novel recurrent CNAs affecting single genes were identified in 3q26.32 (TBL1XR1) and 8q12.1 (TOX). Conclusions: The results obtained are encouraging. Larger archival tissue collections can now be analyzed in order to complement the still fragmented knowledge we have of the genetic basis of the PCNSL. We included samples from 7 PCNSL patients. In 6 out of these 7 PCNSL patients (cases B – G), aCGH experiments were performed in DNA samples obtained from both snap-frozen and FFPE tissues for assay quality comparative purposes. In the remaining sample (case A), only frozen sample was analyzed.
2012-04-29 | E-GEOD-28952 | biostudies-arrayexpress
Project description:Purpose: Only a limited number of genetic studies have been performed in primary central nervous system lymphomas (PCNSL), partly due to the rarity of the tumors and the very limited amount of available tissue. In this report, we present the first molecular characterization of copy-number abnormalities (CNA) of newly diagnosed PCNSL by array-based comparative genomic hybridization in formalin fixed paraffin embedded (FFPE) specimens and compare the results with matched frozen tumor specimens. Experimental design: We performed array-based comparative genomic hybridization (aCGH) in FFPE tissues from PCNSL. Results were compared with matched paired frozen tumors. Results: Our analysis confirmed the good to fair quality and reliability of the data generated from limited amounts of tumoral FFPE tissue. Overall, all PCNSL cases were characterized by highly complex karyotypes with a median of 23 copy-number abnormalities (CNA) per patient (range 17-47). Overall, 20 chromosomal regions were recurrently found in more than 40% of cases. Deletions of 6p21, 6q, 9p21.3 and gain of 12q12-q24.33 were the commonest CNA. Other minimal affected regions were defined, and novel recurrent CNAs affecting single genes were identified in 3q26.32 (TBL1XR1) and 8q12.1 (TOX). Conclusions: The results obtained are encouraging. Larger archival tissue collections can now be analyzed in order to complement the still fragmented knowledge we have of the genetic basis of the PCNSL.
2012-04-30 | GSE28952 | GEO