Dfca63f6-f2b5-418d-9734-c03117b960c4 - samples
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ABSTRACT:
PROVIDER: EGAD00001009165 | EGA |
REPOSITORIES: EGA
Similar Datasets
Project description:We explored the differential methylation patterns found in cfDNA between healthy controls (individuals with no colorectal findings, NCF) and patients with advanced neoplasia (advanced adenomas and colorectal cancer, AA andCRC) using pooled samples, to determine if pooled serum cfDNA samples can be used to search for non-invasive methylation biomarkers, as an affordable and efficient alternative to tissue biopsy. cfDNA was extracted from serum samples and methylation measurements were assessed with the Infinium MethylationEPIC BeadChip. Data was mainly preprocessed and analyzed with R/Bioconductor packages.
2018-04-17 | GSE110185 | GEO
Project description:We explored the differential methylation patterns found in cfDNA between no neoplasia (NN; individuals with no colorectal findings, benign pathologies and non-advanced adenomas) and patients with advanced neoplasia (AN; advanced adenomas and colorectal cancer) using pooled samples, for the discovery of non-invasive methylation biomarkers for CRC screening. cfDNA was extracted from serum samples and methylation measurements were assessed with the Infinium MethylationEPIC BeadChip. Data was mainly preprocessed and analyzed with R/Bioconductor packages.
2023-10-01 | GSE186381 | GEO
Project description:Evaluation of cell free circulating DNA (cfDNA) has recently been proposed for tracking disease relapse in colorectal cancer (CRC). Such assays could overcome the issues of classical monitoring, but requires personalized assay design due to absence of common alteration. On the contrary, early methylation alterations are restricted to delimited genomic loci allowing comprehensive assay design for population study. Our objective was to identify new cancer specific methylation biomarkers fitted to assess cfDNA over treatment, thus monitoring response in the metastatic CRC (mCRC) setup. Genome wide methylation profiling of colorectal cancer cell lines (surrogate to pure tumor tissue) was carried out and compared to publically available normal healthy colon mucosa (cancer unrelated). Identified loci were validated in additional publically available cohorts. Digital PCR assays were designed for selected markers and assessed in cfDNA of self-declared healthy donors (>40 years old), and of mCRC patients. Longitudinal assessment was performed in a subset of colorectal cancer patients treated with different therapy regimen (chemotherapy or targeted agents). Samples from the current GEOset were extracted by Wizard SV Genomic DNA Purification System (Promega). DNA samples were checked for integrity by 1% agarose gel, and quantity via Picogreen quantification. All samples were bisulfite converted using the EZ DNA methylation Gold kit (Zymo Research) with a minimum input of 500ng and following manufacturer’s instructions. Infinium HumanMethylation450 BeadChip arrays were carried out according to the Illumina Infinium HD methylation protocol.
2017-10-10 | GSE86078 | GEO
Project description:This study was conducted to explore the serum methylome of precancerous lesions belonging to the serrated pathway of colorectal carcinogenesis in a prospective multicentre cohort. Individuals were grouped into five main categories: (i) serrated adenocarcinoma (SAC), (ii) high-risk serrated polyps (HR-SP) comprising traditional serrated adenomas (TSA), sessile serrated lesions (SSL), and serrated polyps (SP) with dysplasia or ≥ 10 mm; (iii) high-risk hyperplastic polyps (HR-HP), defined as HP ≥ 10 mm; (iv) low-risk serrated lesions (LR-SL) including SP without dysplasia < 10 mm and HP < 10 mm; and (v) healthy individuals with no colorectal findings (NCF). First, epigenome-wide methylation levels were quantified in pooled cfDNA samples to characterize the differential methylation profile between no serrated neoplasia (NSN: NCF and LR-SL) and high-risk serrated lesions (HR-SL: HR-HP and HR-SP); concordance with tissue methylation levels was assessed using external datasets. Then, the pathway-specific cfDNA methylation signature was evaluated together with cfDNA pools from the conventional CRC pathway. cfDNA was extracted from serum samples and methylation measurements were assessed with the Infinium MethylationEPIC BeadChip. Data was mainly preprocessed and analyzed with R/Bioconductor packages.
2024-03-01 | GSE199173 | GEO
Project description:Background: Liquid biopsies analyzing cell-free DNA methylation in plasma offer a non-invasive diagnostic for diseases, with aging biomarker potential underexplored. Methods: Utilizing enzymatic methyl-seq (EM-seq), this study assessed cfDNA methylation patterns in aging with blood from 35 healthy individuals. Results: It found aging signatures, including higher cfDNA levels and variations in fragment sizes, plus over 2 million age-related differentially methylated CpG sites. A biological age predictive model based on 41 CpG sites showed a strong correlation with chronological age, verified by two datasets. Age-specific epigenetic shifts linked to inflammation were revealed through differentially methylated regions profiling and Olink proteomics. Conclusion: These findings indicate cfDNA methylation as a potential biomarker for aging, and it might exacerbate immunoinflammatory reactivity in older individuals.
2024-05-23 | GSE259312 | GEO
Project description:This study aims to explore genomic features of cancer in plasma WGS data from patients with advanced colorectal cancer. Cell-free DNA (cfDNA) was extracted from plasma using the QIAamp Circulating Nucleic Acid Kit. Libraries were prepared with 5 to 250 ng of cfDNA using the NEBNext DNA Library Prep Kit.
| EGAS00001006377 | EGA
Project description:We performed RNA-seq experiments on a total of 12 mouse immune organs, including spleen (SP), bone marrow (BM), lymph node (LN) and Peripheral blood mononuclear cell (PBMC). Briefly, RNA-Seq libraries were constructed after rRNA depletion using a NEBNext rRNA Depletion Kit (Human/Mouse/Rat) (NEB). The E6310L NEBNext Ultra RNA Library Prep Kit for Illumina（NEB, E7530S）(NEB) was used according to the manufacturer’s instructions and the cDNAs were sequenced with the Hiseq X10 platform(Illumina)
2018-02-12 | E-MTAB-6458 | biostudies-arrayexpress
Project description:Background: Liquid biopsy based on cell free DNA (cfDNA) analysis holds significant promise as a minimally invasive approach for the diagnosis, genotyping and monitoring of solid malignancies. Human tumors release cfDNA in the bloodstream through a combination of events, including cell death, active and passive release. However, the precise mechanisms leading to cfDNA shedding remain to be characterized. Addressing this question in patients is confounded by several factors, such as tumor burden extent, anatomical and vasculature barriers, release of nucleic acids from normal cells. In this work, we exploited cancer models to dissect basic mechanisms of DNA release. Methods: We measured cell loss ratio, doubling time and cfDNA release in the supernatant of a colorectal cancer (CRC) cell line collection (N=76) representative of the molecular subtypes previously identified in cancer patients. Association analyses between quantitative parameters of cfDNA release, cell proliferation and molecular features were evaluated. Functional experiments were performed to test the impact of modulating DNA methylation on cfDNA release. Results: Higher levels of supernatant cfDNA were significantly associated with slower cell cycling and increased cellular crashes. In addition, a higher cfDNA shedding was found in non-CpG Island Methylator Phenotype (CIMP) models. These results indicate a positive correlation between lower methylation and increased cfDNA levels. To explore this further, we exploited methylation microarrays to identify a subset of probes significantly associated with cfDNA shedding and derive a methylation signature capable of discriminating high from low cfDNA releasers. We applied this signature to an independent set of 176 CRC cell lines and patient derived organoids to select 14 models predicted to be low or high releasers. The methylation profile successfully predicted the amount of cfDNA released in the supernatant. At the functional level, genetic ablation of DNA methyl-transferases increased chromatin accessibility and DNA fragmentation, leading to increased cfDNA release in isogenic CRC cell lines. Furthermore, in vitro treatment of five low releaser CRC cells with a demethylating agent was able to induce a significant increase in cfDNA shedding. Conclusion: Methylation status of cancer cell lines contributes to the variability of cfDNA shedding in vitro. Changes in methylation pattern are associated with cfDNA release levels and might be exploited to increase sensitivity of liquid biopsy assays.
2024-09-18 | GSE274189 | GEO
Project description:Colorectal polyp is known a precursor of colorectal cancer (CRC) that holds an increased risk for progression to CRC. Circulating cell-free DNA(cfDNA) methylation has shown favorable performance in the detection and monitoring the malignant progression in a variety of cancers. Here, we conducted a study to discovery cfDNA methylation markers for the diagnosis of CRC. We first performed a genome-wide analysis using the Infinium HumanMethylationEPIC BeadChip array to identify differentially methylated CpGs (DMCs) between 8 CRC and 8 polyp tissues. Then, we validated DMCs in a larger tissue cohort and four methylation markers (cg04486886, cg06712559, cg13539460 and cg27541454) were selected as the methylation markers in tissue by LASSO and random forest models. A diagnosis prediction model was bulit based on the four markers and the methylaion diagnosis score (md-score) can effectively discriminate patients with CRC from polyp tissues. Finally, a single cfDNA methylation marker, cg27541454, was confirmed hypermethylated in CRC in the plasma validation cohort. Together, our findings suggested that the md-score derived from tissue could robustly detect CRC from polpy patients, and cg27541454 may be a promising candidate non-invasive biomarker for CRC early diagnosis.
2024-01-01 | GSE220160 | GEO
Project description:CEH-60 binding profile by comparison of DNA methylation of a C. elegans strain expression ceh-60::dam to a control strain expressing gfp::dam. Sequencing libraries prepared using NEBNext Singleplex oligos for Illumina®. Data analysis performed with GeneDamIDseq (Sharma, Ritler, and Meister 2016).
2020-11-16 | E-MTAB-9539 | biostudies-arrayexpress