Ecdfede6-064a-4136-91b2-adb305553e34 - samples
Ontology highlight
ABSTRACT:
PROVIDER: EGAD00001008838 | EGA |
REPOSITORIES: EGA
Similar Datasets
Project description:36 mouse plasma cell-free DNA cases
| EGAD00001008810 | EGA
Project description:Interventions: Gold Standard:;Index test:
Primary outcome(s): concentration of cell-free DNA in plasma;integrity of cell-free DNA in plasma
Study Design: Diagnostic test: case-control
| 2662278 | ecrin-mdr-crc
Project description:Cell-free DNA fragmentation is a nonrandom process. We showed that cell-free DNA fragments with ends at certain genomic coordinates had higher likelihoods of being derived from hepatocellular carcinoma. Other coordinates were associated with cell-free DNA molecules originating from the liver. Quantitative assessment of cell-free DNA molecules bearing these respective groups of end signatures correlated with the amounts of tumor-derived or liver-derived DNA in plasma. There were millions of tumor-associated plasma DNA end coordinates across the genome. Due to their high prevalence, they were more readily detectable than somatic mutations as a cancer signature in plasma. Hence, detection of tumor-associated plasma DNA ends may offer a cost-effective means of capturing evidence for the presence of cancer through liquid biopsy assessment.
| EGAS00001003160 | EGA
Project description:Background: Cell free DNA (cfDNA) in plasma has received increasing attention and has been studied in a broad range of clinical conditions implicating inflammation, cancer, and aging. However, few studies have focused on mitochondrial DNA (mtDNA) in the cell free form. This study characterized the size distribution and sequence characteristics of plasma cell free mtDNA (cf mtDNA) in humans.Methods and Results: We optimized DNA isolation and next-generation sequencing library preparation protocols to better retain short DNA fragments from plasma, and applied these optimized methods to plasma samples from patients with sepsis. After massive parallel sequencing, we verified that our methods can retain substantially shorter DNA fragments than the standard isolation method, resulting in an average of 11.5 fold increase in short DNA fragments yield (DNA < 100bp). We report that cf mtDNA in plasma is highly enriched in short-size cfDNA (30 ~ 60 bp), which is much shorter than the value previously reported (~140 bp). Motivated by this unique size distribution, we size-selected short cfDNA fragments from the sequencing library, which further increased the mtDNA recovery rate by an average of 10.4 fold. Using this approach we detected mixtures of different mtDNA sequences, termed heteroplasmy, in plasma from 3 patients. In one patient who previously received bone marrow transplantation, different minor allele frequencies were observed between plasma and white blood cells (WBC) at heteroplasmic mtDNA sites, consistent with mixed-tissue origin for plasma DNA.Conclusion: mtDNA in plasma exists as very short fragments that exhibit mtDNA heteroplasmy distribution differences from that found in a single organ/tissue. This study is the first report of genome wide identification of mtDNA heteroplasmy in human plasma. Our optimized method can be used to investigate the potential utility of cf mtDNA fragments and heteroplasmy as biomarkers in various diseases.
2016-05-07 | GSE81178 | GEO