Circulating free DNA: Difference between revisions

Add links
From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
→‎Trauma: Fixed typo
Tags: Mobile edit Mobile web edit
Marketass (talk | contribs)
18 edits
No edit summary
Tags: nowiki added Visual edit
Line 1: Line 1:
{{Orphan|date=July 2016}}
{{Orphan|date=July 2016}}


'''Circulating free DNA (cfDNA)''' are degraded [[DNA]] fragments released to the [[blood plasma]]. cfDNA can be used to describe various forms of DNA freely circulating the bloodstream, including [[circulating tumor DNA| circulating tumor DNA (ctDNA)]] and [[cell-free fetal DNA| cell-free fetal DNA (cffDNA)]]. Elevated levels of cfDNA are observed in [[cancer]], especially in advanced disease.<ref name="MyUser_Ncbi.nlm.nih.gov_March_6_2016c">{{cite journal |title=Circulating free DNA in the management of breast cancer |pmc=4200656 | pmid=25332979 |doi=10.3978/j.issn.2305-5839.2013.06.06 |volume=2 |issue=1 |year=2014 |journal=Ann Transl Med |pages=3 | last1 = Shaw | first1 = JA | last2 = Stebbing | first2 = J}}</ref> There is evidence that cfDNA becomes increasingly frequent in circulation with the onset of age.<ref name="MyUser_Onlinelibrary.wiley.com_March_6_2016c">{{cite journal |title=The dark side of circulating nucleic acids |journal= Aging Cell|volume= 15|issue= 3|pages= 398–399|doi=10.1111/acel.12454|pmid= 26910468|pmc= 4854914|year = 2016|last1 = Gravina|first1 = Silvia|last2= Sedivy|first2= John M.|last3= Vijg|first3= Jan}}</ref> cfDNA has been shown to be a useful [[biomarker]] for a multitude of ailments other than cancer and fetal medicine. This includes but is not limited to trauma, sepsis, aseptic inflammation, myocardial infarction, stroke, transplantation, diabetes, and sickle cell disease.<ref name=":12">{{Cite journal|last=Butt|first=Asif N.|last2=Swaminathan|first2=R.|date=August 2008|title=Overview of Circulating Nucleic Acids in Plasma/Serum|journal=Annals of the New York Academy of Sciences|volume=1137|issue=1|pages=236–242|doi=10.1196/annals.1448.002|pmid=18837954|issn=0077-8923}}</ref>
'''Circulating free DNA (cfDNA)''' are degraded [[DNA]] fragments released to the [[blood plasma]]. cfDNA can be used to describe various forms of DNA freely circulating the bloodstream, including [[circulating tumor DNA| circulating tumor DNA (ctDNA)]] and [[cell-free fetal DNA| cell-free fetal DNA (cffDNA)]]. Elevated levels of cfDNA are observed in [[cancer]], especially in advanced disease.<ref name="MyUser_Ncbi.nlm.nih.gov_March_6_2016c">{{cite journal |title=Circulating free DNA in the management of breast cancer |pmc=4200656 | pmid=25332979 |doi=10.3978/j.issn.2305-5839.2013.06.06 |volume=2 |issue=1 |year=2014 |journal=Ann Transl Med |pages=3 | last1 = Shaw | first1 = JA | last2 = Stebbing | first2 = J}}</ref> There is evidence that cfDNA becomes increasingly frequent in circulation with the onset of age.<ref name="MyUser_Onlinelibrary.wiley.com_March_6_2016c">{{cite journal |title=The dark side of circulating nucleic acids |journal= Aging Cell|volume= 15|issue= 3|pages= 398–399|doi=10.1111/acel.12454|pmid= 26910468|pmc= 4854914|year = 2016|last1 = Gravina|first1 = Silvia|last2= Sedivy|first2= John M.|last3= Vijg|first3= Jan}}</ref> cfDNA has been shown to be a useful [[biomarker]] for a multitude of ailments other than [[cancer]] and fetal [[medicine]]. This includes but is not limited to trauma, [[sepsis]], aseptic [[Inflammation|inflammatio]]<nowiki/>n, myocardial [[Infarction|infarctio]]<nowiki/>n, stroke, [[transplantation]], diabetes, and sickle cell [[disease]].<ref name=":12">{{Cite journal|last=Butt|first=Asif N.|last2=Swaminathan|first2=R.|date=August 2008|title=Overview of Circulating Nucleic Acids in Plasma/Serum|journal=Annals of the New York Academy of Sciences|volume=1137|issue=1|pages=236–242|doi=10.1196/annals.1448.002|pmid=18837954|issn=0077-8923}}</ref> cfDNA is mostly a double-stranded extracellular molecule of DNA, consisting of small fragments (70 to 200 bp) and larger fragments (21 kb). <ref>{{Cite journal|last=Gall|first=Tamara M.H.|last2=Belete|first2=Samuel|last3=Khanderia|first3=Esha|last4=Frampton|first4=Adam E.|last5=Jiao|first5=Long R.|date=2019-1|title=Circulating Tumor Cells and Cell-Free DNA in Pancreatic Ductal Adenocarcinoma|url=https://linkinghub.elsevier.com/retrieve/pii/S0002944017311811|journal=The American Journal of Pathology|language=en|volume=189|issue=1|pages=71–81|doi=10.1016/j.ajpath.2018.03.020}}</ref> and has been recognized as an accurate marker for the [[diagnosis]] of [[Prostate cancer|prostat]]<nowiki/>e cancer and [[breast cancer]]. <ref>{{Cite web|url=https://www.hindawi.com/journals/bmri/2013/270457/|title=Urine Cell-Free DNA Integrity as a Marker for Early Prostate Cancer Diagnosis: A Pilot Study|last=Zoli|first=Wainer|last2=Silvestrini|first2=Rosella|date=2013|website=BioMed Research International|language=en|doi=10.1155/2013/270457|pmc=PMC3586456|pmid=23509700|access-date=2019-04-30|last3=Amadori|first3=Dino|last4=Carretta|first4=Elisa|last5=Gunelli|first5=Roberta|last6=Salvi|first6=Samanta|last7=Calistri|first7=Daniele|last8=Casadio|first8=Valentina}}</ref>

Other publications confirm the origin of cfDNA from [[Carcinoma|carcinomas]] and cfDNA occurs in patients with advanced [[cancer]]. Cell‐free DNA (cfDNA) is present in the circulating [[plasma]], also in other body fluids. <ref>{{Cite journal|last=Teo|first=Yee Voan|last2=Capri|first2=Miriam|last3=Morsiani|first3=Cristina|last4=Pizza|first4=Grazia|last5=Faria|first5=Ana Maria Caetano|last6=Franceschi|first6=Claudio|last7=Neretti|first7=Nicola|date=2019-2|title=Cell-free DNA as a biomarker of aging|url=http://doi.wiley.com/10.1111/acel.12890|journal=Aging Cell|language=en|volume=18|issue=1|pages=e12890|doi=10.1111/acel.12890|pmc=PMC6351822|pmid=30575273}}</ref>

The release of cfDNA into the [[bloodstream]] appears by different reasons, including the primary [[Neoplasm|tumor]], [[tumor cell]]<nowiki/>s that circulate in [[peripheral blood]], metastatic deposits present at distant sites, and normal cell types, like [[Hematopoietic cell|hematopoietic]] and [[Stromal cell|stromal cells]]. [[Tumor cells]] and cfDNA circulate in the [[bloodstream]] of patients with [[cancer]]. Its rapidly increased accumulation in blood during tumor development is caused by an excessive DNA release by apoptotic cells and necrotic cells. Active secretion within exosomes has been discussed, but it is still we dont know whether this is a relevant or rather minor source of cfDNA. <ref>{{Cite journal|last=Thakur, Zhang H, BECKER A, MATEI I, HUANG Y, COSTA-SILVA B|date=2014|title=Double-stranded DNA in exosomes: a novel biomarker in cancer detection.|url=|journal=Cell Research|volume=|pages=|via=}}</ref>

cfDNA circulates predominantly as [[Nucleosome|nucleosomes]], which are nuclear complexes of histones and DNA <ref>{{Cite journal|last=Roth|first=Carina|last2=Pantel|first2=Klaus|last3=Müller|first3=Volkmar|last4=Rack|first4=Brigitte|last5=Kasimir-Bauer|first5=Sabine|last6=Janni|first6=Wolfgang|last7=Schwarzenbach|first7=Heidi|date=2011-01-06|title=Apoptosis-related deregulation of proteolytic activities and high serum levels of circulating nucleosomes and DNA in blood correlate with breast cancer progression|url=https://doi.org/10.1186/1471-2407-11-4|journal=BMC Cancer|volume=11|issue=1|pages=4|doi=10.1186/1471-2407-11-4|issn=1471-2407|pmc=PMC3024991|pmid=21211028}}</ref>. They are frequently nonspecifically elevated in [[cancer]] but may be more specific for monitoring cytotoxic cancer therapy, mainly for the early estimation of therapy efficacy. <ref>{{Cite journal|last=Stoetzer|first=Oliver J.|last2=Fersching|first2=Debora M.I.|last3=Salat|first3=Christoph|last4=Steinkohl|first4=Oliver|last5=Gabka|first5=Christian J.|last6=Hamann|first6=Ulrich|last7=Braun|first7=Michael|last8=Feller|first8=Axel-Mario|last9=Heinemann|first9=Volker|date=2013-8|title=Prediction of response to neoadjuvant chemotherapy in breast cancer patients by circulating apoptotic biomarkers nucleosomes, DNAse, cytokeratin-18 fragments and survivin|url=https://linkinghub.elsevier.com/retrieve/pii/S0304383513003479|journal=Cancer Letters|language=en|volume=336|issue=1|pages=140–148|doi=10.1016/j.canlet.2013.04.013}}</ref>


== History ==
== History ==
Circulated cell-free DNA was first discovered by Mandel and Metais in 1948.<ref>{{Cite journal|last=Mandel|first=P.|last2=Metais|first2=P.|date=February 1948|title=[Not Available]|journal=Comptes Rendus des Séances de la Société de Biologie et de ses Filiales|volume=142|issue=3–4|pages=241–243|issn=0037-9026|pmid=18875018}}</ref> It was later discovered that the level of cfDNA is significantly increased in the plasma of diseased patients. This discovery was first made in Lupus patients<ref>{{Cite journal|last=Tan|first=E M|last2=Schur|first2=P H|last3=Carr|first3=R I|last4=Kunkel|first4=H G|date=1966-11-01|title=Deoxybonucleic acid (DNA) and antibodies to DNA in the serum of patients with systemic lupus erythematosus.|journal=Journal of Clinical Investigation|volume=45|issue=11|pages=1732–1740|doi=10.1172/jci105479|pmid=4959277|pmc=292857|issn=0021-9738}}</ref> and later it was determined that the levels of cfDNA are elevated in over half of cancer patients.<ref>{{Cite journal|last=Leon|first=S. A.|last2=Shapiro|first2=B.|last3=Sklaroff|first3=D. M.|last4=Yaros|first4=M. J.|date=March 1977|title=Free DNA in the serum of cancer patients and the effect of therapy|journal=Cancer Research|volume=37|issue=3|pages=646–650|issn=0008-5472|pmid=837366}}</ref> This increase in cfDNA in cancer patients has been shown to be due to [[circulating tumor cell]]s (CTC) traveling in the peripheral blood. The ability to extract [[circulating tumor DNA]] (ctDNA) from the human plasma has led to huge advancements in noninvasive cancer detection.<ref>{{Cite journal|last=Sorenson|first=G. D.|last2=Pribish|first2=D. M.|last3=Valone|first3=F. H.|last4=Memoli|first4=V. A.|last5=Bzik|first5=D. J.|last6=Yao|first6=S. L.|date=January 1994|title=Soluble normal and mutated DNA sequences from single-copy genes in human blood|journal=Cancer Epidemiology, Biomarkers & Prevention|volume=3|issue=1|pages=67–71|issn=1055-9965|pmid=8118388}}</ref> Most notably, it has led to what is now known as [[Liquid biopsy|Liquid Biopsy]]. In short, liquid biopsy is using biomarkers and cancer cells in the blood as a means of diagnosing cancer type and stage.<ref>{{Cite journal|last=Arneth|first=Borros|date=2018-05-04|title=Update on the types and usage of liquid biopsies in the clinical setting: a systematic review|url=https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5935950/|journal=BMC Cancer|volume=18|issue=1|pages=527|doi=10.1186/s12885-018-4433-3|issn=1471-2407|pmc=5935950|pmid=29728089}}</ref> This type of biopsy is noninvasive and allows for the routine clinical screening that is important in determining cancer relapse after initial treatment.<ref>{{Cite journal|last=Babayan|first=Anna|last2=Pantel|first2=Klaus|date=2018-03-20|title=Advances in liquid biopsy approaches for early detection and monitoring of cancer|url=https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5861602/|journal=Genome Medicine|volume=10|issue=1|pages=21|doi=10.1186/s13073-018-0533-6|issn=1756-994X|pmc=5861602|pmid=29558971}}</ref>
Circulated cell-free DNA was first discovered by Mandel and Metais in 1948.<ref>{{Cite journal|last=Mandel|first=P.|last2=Metais|first2=P.|date=February 1948|title=[Not Available]|journal=Comptes Rendus des Séances de la Société de Biologie et de ses Filiales|volume=142|issue=3–4|pages=241–243|issn=0037-9026|pmid=18875018}}</ref> It was later discovered that the level of cfDNA is significantly increased in the plasma of diseased patients. This discovery was first made in Lupus patients<ref>{{Cite journal|last=Tan|first=E M|last2=Schur|first2=P H|last3=Carr|first3=R I|last4=Kunkel|first4=H G|date=1966-11-01|title=Deoxybonucleic acid (DNA) and antibodies to DNA in the serum of patients with systemic lupus erythematosus.|journal=Journal of Clinical Investigation|volume=45|issue=11|pages=1732–1740|doi=10.1172/jci105479|pmid=4959277|pmc=292857|issn=0021-9738}}</ref> and later it was determined that the levels of cfDNA are elevated in over half of cancer patients.<ref>{{Cite journal|last=Leon|first=S. A.|last2=Shapiro|first2=B.|last3=Sklaroff|first3=D. M.|last4=Yaros|first4=M. J.|date=March 1977|title=Free DNA in the serum of cancer patients and the effect of therapy|journal=Cancer Research|volume=37|issue=3|pages=646–650|issn=0008-5472|pmid=837366}}</ref> This increase in cfDNA in cancer patients has been shown to be due to [[circulating tumor cell]]s (CTC) traveling in the peripheral blood. The ability to extract [[circulating tumor DNA]] (ctDNA) from the human plasma has led to huge advancements in noninvasive cancer detection.<ref>{{Cite journal|last=Sorenson|first=G. D.|last2=Pribish|first2=D. M.|last3=Valone|first3=F. H.|last4=Memoli|first4=V. A.|last5=Bzik|first5=D. J.|last6=Yao|first6=S. L.|date=January 1994|title=Soluble normal and mutated DNA sequences from single-copy genes in human blood|journal=Cancer Epidemiology, Biomarkers & Prevention|volume=3|issue=1|pages=67–71|issn=1055-9965|pmid=8118388}}</ref> Most notably, it has led to what is now known as [[Liquid biopsy|Liquid Biopsy]]. In short, liquid biopsy is using biomarkers and [[cancer cell]]<nowiki/>s in the blood as a means of diagnosing cancer type and stage.<ref>{{Cite journal|last=Arneth|first=Borros|date=2018-05-04|title=Update on the types and usage of liquid biopsies in the clinical setting: a systematic review|url=https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5935950/|journal=BMC Cancer|volume=18|issue=1|pages=527|doi=10.1186/s12885-018-4433-3|issn=1471-2407|pmc=5935950|pmid=29728089}}</ref> This type of biopsy is noninvasive and allows for the routine clinical screening that is important in determining cancer relapse after initial treatment.<ref>{{Cite journal|last=Babayan|first=Anna|last2=Pantel|first2=Klaus|date=2018-03-20|title=Advances in liquid biopsy approaches for early detection and monitoring of cancer|url=https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5861602/|journal=Genome Medicine|volume=10|issue=1|pages=21|doi=10.1186/s13073-018-0533-6|issn=1756-994X|pmc=5861602|pmid=29558971}}</ref>

== Based on intracellular origin, cfDNA and immune system ==
The intracellular origin of cfDNA, e.g., either from [[nucleus]] or [[Mitochondrion|mitochondria]], can also influence the inflammatory potential of cfDNA. MtDNA, nuclear DNA, is a potent [[Inflammatory|inflammatory trigger]].<ref>{{Cite journal|last=Lood|first=Christian|last2=Blanco|first2=Luz P|last3=Purmalek|first3=Monica M|last4=Carmona-Rivera|first4=Carmelo|last5=De Ravin|first5=Suk S|last6=Smith|first6=Carolyne K|last7=Malech|first7=Harry L|last8=Ledbetter|first8=Jeffrey A|last9=Elkon|first9=Keith B|date=2016-2|title=Neutrophil extracellular traps enriched in oxidized mitochondrial DNA are interferogenic and contribute to lupus-like disease|url=http://www.nature.com/articles/nm.4027|journal=Nature Medicine|language=en|volume=22|issue=2|pages=146–153|doi=10.1038/nm.4027|issn=1078-8956|pmc=PMC4742415|pmid=26779811}}</ref> MtDNA, due to its prokaryotic origin, holds many features that are similar to [[Bacteria|bacterial]] DNA, including the presence of a relatively high content of unmethylated CpG motifs, which are rarely observed in nuclear DNA. <ref>{{Cite journal|last=Yang|first=D.|last2=Oyaizu|first2=Y.|last3=Oyaizu|first3=H.|last4=Olsen|first4=G. J.|last5=Woese|first5=C. R.|date=1985-07-01|title=Mitochondrial origins.|url=http://www.pnas.org/cgi/doi/10.1073/pnas.82.13.4443|journal=Proceedings of the National Academy of Sciences|language=en|volume=82|issue=13|pages=4443–4447|doi=10.1073/pnas.82.13.4443|issn=0027-8424}}</ref> The unmethylated CpG motifs are of particular importance as [[TLR9]], the only endolysosomal DNA-sensing receptor, has a unique specificity for unmethylated CpG [[DNA]]. [[mtDNA]] was shown to activate [[Neutrophil|neutrophils]] through [[TLR9]] engagement <ref>{{Cite journal|last=Zhang|first=Qin|last2=Raoof|first2=Mustafa|last3=Chen|first3=Yu|last4=Sumi|first4=Yuka|last5=Sursal|first5=Tolga|last6=Junger|first6=Wolfgang|last7=Brohi|first7=Karim|last8=Itagaki|first8=Kiyoshi|last9=Hauser|first9=Carl J.|date=2010-3|title=Circulating mitochondrial DAMPs cause inflammatory responses to injury|url=http://www.nature.com/articles/nature08780|journal=Nature|language=en|volume=464|issue=7285|pages=104–107|doi=10.1038/nature08780|issn=0028-0836|pmc=PMC2843437|pmid=20203610}}</ref> unless coupled to carrier [[Protein|proteins]], mtDNA, but not [[nuclear]] DNA, can be recognized as a danger-associated molecular pattern inducing pro-inflammation through [[TLR9]]. <ref name=":0">{{Cite journal|last=Collins|first=L. Vincent|last2=Hajizadeh|first2=Shahin|last3=Holme|first3=Elisabeth|last4=Jonsson|first4=Ing-Marie|last5=Tarkowski|first5=Andrej|date=2004-6|title=Endogenously oxidized mitochondrial DNA induces in vivo and in vitro inflammatory responses|url=http://doi.wiley.com/10.1189/jlb.0703328|journal=Journal of Leukocyte Biology|language=en|volume=75|issue=6|pages=995–1000|doi=10.1189/jlb.0703328}}</ref> Collins et al. reported that intra-articular injection of mtDNA induces arthritis in vivo, proposing a direct role of mtDNA extrusion in the disease pathogenesis of RA .<ref name=":0" />

[[Mitochondrial DNA|MtDNA]], in contrast to nuclear DNA, is characterized by elevated basal levels of 8-OHdG, a marker of oxidative damage. The high content of oxidative damage in mtDNA is attributed to the close proximity of mtDNA to ROS and relatively inefficient DNA repair mechanisms that can lead to the accumulation of DNA lesions. <ref>{{Citation|last=Clayton|first=David A.|title=Absence of a Pyrimidine Dimer Repair Mechanism for Mitochondrial DNA in Mouse and Human Cells|date=1975|url=http://link.springer.com/10.1007/978-1-4684-2898-8_26|work=Molecular Mechanisms for Repair of DNA|pages=589–591|editor-last=Hanawalt|editor-first=Philip C.|publisher=Springer US|language=en|doi=10.1007/978-1-4684-2898-8_26|isbn=9781468429008|access-date=2019-04-30|last2=Doda|first2=Jackie N.|last3=Friedberg|first3=Errol C.|editor2-last=Setlow|editor2-first=Richard B.}}</ref>

They have shown that oxidative burst during NETosis can oxidize [[Mitochondrial DNA|mtDNA]] and the released oxidized mtDNA by itself, or in complex with TFAM, can generate prominent induction of type I IFNs. <ref>{{Cite journal|last=Lood|first=Christian|last2=Blanco|first2=Luz P|last3=Purmalek|first3=Monica M|last4=Carmona-Rivera|first4=Carmelo|last5=De Ravin|first5=Suk S|last6=Smith|first6=Carolyne K|last7=Malech|first7=Harry L|last8=Ledbetter|first8=Jeffrey A|last9=Elkon|first9=Keith B|date=2016-2|title=Neutrophil extracellular traps enriched in oxidized mitochondrial DNA are interferogenic and contribute to lupus-like disease|url=http://www.nature.com/articles/nm.4027|journal=Nature Medicine|language=en|volume=22|issue=2|pages=146–153|doi=10.1038/nm.4027|issn=1078-8956|pmc=PMC4742415|pmid=26779811}}</ref> Oxidized mtDNA generated during programmed cell death is not limited to activate TLR9, but was shown to also engage the NRLP3 inflammasome, leading to the production of pro-inflammatory [[Cytokine|cytokines]], [[IL-1β]], and [[IL-18]]. <ref>{{Cite journal|last=Shimada|first=Kenichi|last2=Crother|first2=Timothy R.|last3=Karlin|first3=Justin|last4=Dagvadorj|first4=Jargalsaikhan|last5=Chiba|first5=Norika|last6=Chen|first6=Shuang|last7=Ramanujan|first7=V. Krishnan|last8=Wolf|first8=Andrea J.|last9=Vergnes|first9=Laurent|date=2012-3|title=Oxidized Mitochondrial DNA Activates the NLRP3 Inflammasome during Apoptosis|url=https://linkinghub.elsevier.com/retrieve/pii/S1074761312000441|journal=Immunity|language=en|volume=36|issue=3|pages=401–414|doi=10.1016/j.immuni.2012.01.009|pmc=PMC3312986|pmid=22342844}}</ref> [[Mitochondrial DNA|MtDN]]A can also be recognized by cyclic [[GMP synthase (glutamine—hydrolysing)|GMP]]-AMP synthase (cGAS), a cytosolic [[dsDNA]] sensor to initiate a STING-IRF3-dependent pathway that in turn orchestrates the production of type I IFNs. <ref>{{Cite journal|last=West|first=A. Phillip|last2=Khoury-Hanold|first2=William|last3=Staron|first3=Matthew|last4=Tal|first4=Michal C.|last5=Pineda|first5=Cristiana M.|last6=Lang|first6=Sabine M.|last7=Bestwick|first7=Megan|last8=Duguay|first8=Brett A.|last9=Raimundo|first9=Nuno|date=2015-4|title=Mitochondrial DNA stress primes the antiviral innate immune response|url=http://www.nature.com/articles/nature14156|journal=Nature|language=en|volume=520|issue=7548|pages=553–557|doi=10.1038/nature14156|issn=0028-0836|pmc=PMC4409480|pmid=25642965}}</ref>


== Methods ==
== Methods ==
Line 12: Line 25:


=== Analysis of cfDNA in Plasma ===
=== Analysis of cfDNA in Plasma ===
[[File:Continuous flow PCR schematic.png|thumb|334x334px]]


==== PCR ====
==== PCR ====
Line 35: Line 49:
=== Transplant Graft Rejection ===
=== Transplant Graft Rejection ===
Foreign cfDNA has been shown to be present in the plasma of solid organ transplant patients. This cfDNA is derived from the grafted organ and is termed GcfDNA. GcfDNA values spike initially after a transplant procedure (>5%) and typically drop down (<0.5%) within one week.<ref name=":02">{{Cite journal|last=Beck|first=J.|last2=Oellerich|first2=M.|last3=Schulz|first3=U.|last4=Schauerte|first4=V.|last5=Reinhard|first5=L.|last6=Fuchs|first6=U.|last7=Knabbe|first7=C.|last8=Zittermann|first8=A.|last9=Olbricht|first9=C.|date=October 2015|title=Donor-Derived Cell-Free DNA Is a Novel Universal Biomarker for Allograft Rejection in Solid Organ Transplantation|journal=Transplantation Proceedings|volume=47|issue=8|pages=2400–2403|doi=10.1016/j.transproceed.2015.08.035|pmid=26518940|issn=0041-1345}}</ref> If the host body rejects the grafted organ the GcfDNA concentration in the blood will rise to a level greater than 5-fold higher than those without complications. This increase in GcfDNA can be detected prior to any other clinical or biochemical signs of complication.<ref name=":02" />
Foreign cfDNA has been shown to be present in the plasma of solid organ transplant patients. This cfDNA is derived from the grafted organ and is termed GcfDNA. GcfDNA values spike initially after a transplant procedure (>5%) and typically drop down (<0.5%) within one week.<ref name=":02">{{Cite journal|last=Beck|first=J.|last2=Oellerich|first2=M.|last3=Schulz|first3=U.|last4=Schauerte|first4=V.|last5=Reinhard|first5=L.|last6=Fuchs|first6=U.|last7=Knabbe|first7=C.|last8=Zittermann|first8=A.|last9=Olbricht|first9=C.|date=October 2015|title=Donor-Derived Cell-Free DNA Is a Novel Universal Biomarker for Allograft Rejection in Solid Organ Transplantation|journal=Transplantation Proceedings|volume=47|issue=8|pages=2400–2403|doi=10.1016/j.transproceed.2015.08.035|pmid=26518940|issn=0041-1345}}</ref> If the host body rejects the grafted organ the GcfDNA concentration in the blood will rise to a level greater than 5-fold higher than those without complications. This increase in GcfDNA can be detected prior to any other clinical or biochemical signs of complication.<ref name=":02" />

== Future directions ==
[[File:ELISA diretto e sandwich.png|thumb]]
cfDNA allows a rapid, easy, non-invasive and repetitive method of sampling. A combination of these biological features and technical feasibility of sampling, position cfDNA as a potential [[biomarker]] of enormous utility for example for autoimmune rheumatic diseases or tumors. However, this metod lacks uniformity on the type of [[sample]] (plasma/serum/synovial fluid), methods of sample collection/processing, free or cell-surface bound DNA, cfDNA extraction and cfDNA quantification, and also in the presentation and interpretation of quantitative cfDNA findings. <ref>{{Cite journal|last=Duvvuri|first=Bhargavi|last2=Lood|first2=Christian|date=2019-03-19|title=Cell-Free DNA as a Biomarker in Autoimmune Rheumatic Diseases|url=https://www.frontiersin.org/article/10.3389/fimmu.2019.00502/full|journal=Frontiers in Immunology|volume=10|doi=10.3389/fimmu.2019.00502|issn=1664-3224|pmc=PMC6433826|pmid=30941136}}</ref>

cfDNA is quantified by fluorescence methods, such as PicoGreen staining and ultraviolet spectrometry, the more sensitive is quantitative polymerase chain reaction (PCR; SYBR Green or TaqMan) of repetitive elements or housekeeping genes. Circulating nucleosomes, they are the primary repeating unit of DNA organization in chromatin, are quantified by enzyme-linked immunosorbent assays [[ELISA|(ELISA]]). <ref>{{Cite journal|last=Pinzani|first=Pamela|last2=Salvianti|first2=Francesca|last3=Pazzagli|first3=Mario|last4=Orlando|first4=Claudio|date=2010-4|title=Circulating nucleic acids in cancer and pregnancy|url=https://linkinghub.elsevier.com/retrieve/pii/S104620231000054X|journal=Methods|language=en|volume=50|issue=4|pages=302–307|doi=10.1016/j.ymeth.2010.02.004}}</ref>


==References==
==References==

Revision as of 20:21, 30 April 2019

Circulating free DNA (cfDNA) are degraded DNA fragments released to the blood plasma. cfDNA can be used to describe various forms of DNA freely circulating the bloodstream, including circulating tumor DNA (ctDNA) and cell-free fetal DNA (cffDNA). Elevated levels of cfDNA are observed in cancer, especially in advanced disease.[1] There is evidence that cfDNA becomes increasingly frequent in circulation with the onset of age.[2] cfDNA has been shown to be a useful biomarker for a multitude of ailments other than cancer and fetal medicine. This includes but is not limited to trauma, sepsis, aseptic inflammation, myocardial infarction, stroke, transplantation, diabetes, and sickle cell disease.[3] cfDNA is mostly a double-stranded extracellular molecule of DNA, consisting of small fragments (70 to 200 bp) and larger fragments (21 kb). [4] and has been recognized as an accurate marker for the diagnosis of prostate cancer and breast cancer. [5]

Other publications confirm the origin of cfDNA from carcinomas and cfDNA occurs in patients with advanced cancer. Cell‐free DNA (cfDNA) is present in the circulating plasma, also in other body fluids. [6]

The release of cfDNA into the bloodstream appears by different reasons, including the primary tumor, tumor cells that circulate in peripheral blood, metastatic deposits present at distant sites, and normal cell types, like hematopoietic and stromal cells. Tumor cells and cfDNA circulate in the bloodstream of patients with cancer. Its rapidly increased accumulation in blood during tumor development is caused by an excessive DNA release by apoptotic cells and necrotic cells. Active secretion within exosomes has been discussed, but it is still we dont know whether this is a relevant or rather minor source of cfDNA. [7]

cfDNA circulates predominantly as nucleosomes, which are nuclear complexes of histones and DNA [8]. They are frequently nonspecifically elevated in cancer but may be more specific for monitoring cytotoxic cancer therapy, mainly for the early estimation of therapy efficacy. [9]

History

Circulated cell-free DNA was first discovered by Mandel and Metais in 1948.[10] It was later discovered that the level of cfDNA is significantly increased in the plasma of diseased patients. This discovery was first made in Lupus patients[11] and later it was determined that the levels of cfDNA are elevated in over half of cancer patients.[12] This increase in cfDNA in cancer patients has been shown to be due to circulating tumor cells (CTC) traveling in the peripheral blood. The ability to extract circulating tumor DNA (ctDNA) from the human plasma has led to huge advancements in noninvasive cancer detection.[13] Most notably, it has led to what is now known as Liquid Biopsy. In short, liquid biopsy is using biomarkers and cancer cells in the blood as a means of diagnosing cancer type and stage.[14] This type of biopsy is noninvasive and allows for the routine clinical screening that is important in determining cancer relapse after initial treatment.[15]

Based on intracellular origin, cfDNA and immune system

The intracellular origin of cfDNA, e.g., either from nucleus or mitochondria, can also influence the inflammatory potential of cfDNA. MtDNA, nuclear DNA, is a potent inflammatory trigger.[16] MtDNA, due to its prokaryotic origin, holds many features that are similar to bacterial DNA, including the presence of a relatively high content of unmethylated CpG motifs, which are rarely observed in nuclear DNA. [17] The unmethylated CpG motifs are of particular importance as TLR9, the only endolysosomal DNA-sensing receptor, has a unique specificity for unmethylated CpG DNA. mtDNA was shown to activate neutrophils through TLR9 engagement [18] unless coupled to carrier proteins, mtDNA, but not nuclear DNA, can be recognized as a danger-associated molecular pattern inducing pro-inflammation through TLR9. [19] Collins et al. reported that intra-articular injection of mtDNA induces arthritis in vivo, proposing a direct role of mtDNA extrusion in the disease pathogenesis of RA .[19]

MtDNA, in contrast to nuclear DNA, is characterized by elevated basal levels of 8-OHdG, a marker of oxidative damage. The high content of oxidative damage in mtDNA is attributed to the close proximity of mtDNA to ROS and relatively inefficient DNA repair mechanisms that can lead to the accumulation of DNA lesions. [20]

They have shown that oxidative burst during NETosis can oxidize mtDNA and the released oxidized mtDNA by itself, or in complex with TFAM, can generate prominent induction of type I IFNs. [21] Oxidized mtDNA generated during programmed cell death is not limited to activate TLR9, but was shown to also engage the NRLP3 inflammasome, leading to the production of pro-inflammatory cytokines, IL-1β, and IL-18. [22] MtDNA can also be recognized by cyclic GMP-AMP synthase (cGAS), a cytosolic dsDNA sensor to initiate a STING-IRF3-dependent pathway that in turn orchestrates the production of type I IFNs. [23]

Methods

Collection and purification

cfDNA purification is prone to contamination due to ruptured blood cells during the purification process.[24] Because of this, different purification methods can lead to significantly different cfDNA extraction yields.[25][26] At the moment, typical purification methods involve collection of blood via venipuncture, centrifugation to pellet the cells, and extraction of cfDNA from the plasma. The specific method for extraction of cfDNA from the plasma depends on the protocol desired.[27]

Analysis of cfDNA in Plasma

PCR

In general, the detection of specific DNA sequences in cfDNA can be done by two means; sequence specific detection (PCR based) and general genomic analysis of all cfDNA present in the blood (DNA sequencing).[28] The presence of cfDNA containing DNA from tumor cells was originally characterized using PCR amplification of mutated genes from extracted cfDNA.[29] PCR based analysis of cfDNA typically rely on the analytical nature of qPCR and digital PCR. Both of these techniques can detect down to a single targeted molecule present in a sample. For this reason the PCR based method of detection is still very prominent tool in cfDNA detection. This method has the limitation of not being able to detect larger structural variant present in ctDNA and for this reason massively parallel next generation sequencing is also used to determine ctDNA content in cfDNA

Massively Parallel Sequencing

Massively parallel sequencing (MPS) has allowed the deep sequencing of cfDNA. this deep sequencing is required to detect ctDNA present in low concentrations in the plasma. Two main sequencing techniques are typically used for analysis of cfDNA; PCR amplicon sequencing[30] and hybrid capture sequencing.[31]

cfDNA and Illness

Cancer

The majority of cfDNA research is focused on DNA originating from circulating tumor cells (ctDNA). In short, the DNA from circulating tumor cells gets released by means that are not fully understood.[32]

Trauma

Elevated cfDNA has been detected with acute blunt trauma[33] and burn victims.[34] In both of these cases cfDNA concentration in the plasma were correlated to the severity of the injury, as well as outcome of the patient.

Sepsis

It has been shown that an increase cfDNA in the plasma of ICU patients is an indicator of the onset of sepsis.[35][36] Due to the severity of sepsis in ICU patients, further testing in order to determine the scope of cfDNA efficacy as a biomarker for septic risk is likely.[3]

Myocardial Infraction

Patients showing signs of myocardial infraction have been shown to have elevated cfDNA levels.[37] This elevation correlates to patient outcome in terms of additional cardiac issues and even mortality within two years.[38]

Transplant Graft Rejection

Foreign cfDNA has been shown to be present in the plasma of solid organ transplant patients. This cfDNA is derived from the grafted organ and is termed GcfDNA. GcfDNA values spike initially after a transplant procedure (>5%) and typically drop down (<0.5%) within one week.[39] If the host body rejects the grafted organ the GcfDNA concentration in the blood will rise to a level greater than 5-fold higher than those without complications. This increase in GcfDNA can be detected prior to any other clinical or biochemical signs of complication.[39]

Future directions

cfDNA allows a rapid, easy, non-invasive and repetitive method of sampling. A combination of these biological features and technical feasibility of sampling, position cfDNA as a potential biomarker of enormous utility for example for autoimmune rheumatic diseases or tumors. However, this metod lacks uniformity on the type of sample (plasma/serum/synovial fluid), methods of sample collection/processing, free or cell-surface bound DNA, cfDNA extraction and cfDNA quantification, and also in the presentation and interpretation of quantitative cfDNA findings. [40]

cfDNA is quantified by fluorescence methods, such as PicoGreen staining and ultraviolet spectrometry, the more sensitive is quantitative polymerase chain reaction (PCR; SYBR Green or TaqMan) of repetitive elements or housekeeping genes. Circulating nucleosomes, they are the primary repeating unit of DNA organization in chromatin, are quantified by enzyme-linked immunosorbent assays (ELISA). [41]

References

  1. ^ Shaw, JA; Stebbing, J (2014). "Circulating free DNA in the management of breast cancer". Ann Transl Med. 2 (1): 3. doi:10.3978/j.issn.2305-5839.2013.06.06. PMC 4200656. PMID 25332979.
  2. ^ Gravina, Silvia; Sedivy, John M.; Vijg, Jan (2016). "The dark side of circulating nucleic acids". Aging Cell. 15 (3): 398–399. doi:10.1111/acel.12454. PMC 4854914. PMID 26910468.
  3. ^ a b Butt, Asif N.; Swaminathan, R. (August 2008). "Overview of Circulating Nucleic Acids in Plasma/Serum". Annals of the New York Academy of Sciences. 1137 (1): 236–242. doi:10.1196/annals.1448.002. ISSN 0077-8923. PMID 18837954.
  4. ^ Gall, Tamara M.H.; Belete, Samuel; Khanderia, Esha; Frampton, Adam E.; Jiao, Long R. (2019-1). "Circulating Tumor Cells and Cell-Free DNA in Pancreatic Ductal Adenocarcinoma". The American Journal of Pathology. 189 (1): 71–81. doi:10.1016/j.ajpath.2018.03.020. {{cite journal}}: Check date values in: |date= (help)
  5. ^ Zoli, Wainer; Silvestrini, Rosella; Amadori, Dino; Carretta, Elisa; Gunelli, Roberta; Salvi, Samanta; Calistri, Daniele; Casadio, Valentina (2013). "Urine Cell-Free DNA Integrity as a Marker for Early Prostate Cancer Diagnosis: A Pilot Study". BioMed Research International. doi:10.1155/2013/270457. PMC 3586456. PMID 23509700. Retrieved 2019-04-30.{{cite web}}: CS1 maint: PMC format (link) CS1 maint: unflagged free DOI (link)
  6. ^ Teo, Yee Voan; Capri, Miriam; Morsiani, Cristina; Pizza, Grazia; Faria, Ana Maria Caetano; Franceschi, Claudio; Neretti, Nicola (2019-2). "Cell-free DNA as a biomarker of aging". Aging Cell. 18 (1): e12890. doi:10.1111/acel.12890. PMC 6351822. PMID 30575273. {{cite journal}}: Check date values in: |date= (help)CS1 maint: PMC format (link)
  7. ^ Thakur, Zhang H, BECKER A, MATEI I, HUANG Y, COSTA-SILVA B (2014). "Double-stranded DNA in exosomes: a novel biomarker in cancer detection". Cell Research.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  8. ^ Roth, Carina; Pantel, Klaus; Müller, Volkmar; Rack, Brigitte; Kasimir-Bauer, Sabine; Janni, Wolfgang; Schwarzenbach, Heidi (2011-01-06). "Apoptosis-related deregulation of proteolytic activities and high serum levels of circulating nucleosomes and DNA in blood correlate with breast cancer progression". BMC Cancer. 11 (1): 4. doi:10.1186/1471-2407-11-4. ISSN 1471-2407. PMC 3024991. PMID 21211028.{{cite journal}}: CS1 maint: PMC format (link) CS1 maint: unflagged free DOI (link)
  9. ^ Stoetzer, Oliver J.; Fersching, Debora M.I.; Salat, Christoph; Steinkohl, Oliver; Gabka, Christian J.; Hamann, Ulrich; Braun, Michael; Feller, Axel-Mario; Heinemann, Volker (2013-8). "Prediction of response to neoadjuvant chemotherapy in breast cancer patients by circulating apoptotic biomarkers nucleosomes, DNAse, cytokeratin-18 fragments and survivin". Cancer Letters. 336 (1): 140–148. doi:10.1016/j.canlet.2013.04.013. {{cite journal}}: Check date values in: |date= (help)
  10. ^ Mandel, P.; Metais, P. (February 1948). "[Not Available]". Comptes Rendus des Séances de la Société de Biologie et de ses Filiales. 142 (3–4): 241–243. ISSN 0037-9026. PMID 18875018.
  11. ^ Tan, E M; Schur, P H; Carr, R I; Kunkel, H G (1966-11-01). "Deoxybonucleic acid (DNA) and antibodies to DNA in the serum of patients with systemic lupus erythematosus". Journal of Clinical Investigation. 45 (11): 1732–1740. doi:10.1172/jci105479. ISSN 0021-9738. PMC 292857. PMID 4959277.
  12. ^ Leon, S. A.; Shapiro, B.; Sklaroff, D. M.; Yaros, M. J. (March 1977). "Free DNA in the serum of cancer patients and the effect of therapy". Cancer Research. 37 (3): 646–650. ISSN 0008-5472. PMID 837366.
  13. ^ Sorenson, G. D.; Pribish, D. M.; Valone, F. H.; Memoli, V. A.; Bzik, D. J.; Yao, S. L. (January 1994). "Soluble normal and mutated DNA sequences from single-copy genes in human blood". Cancer Epidemiology, Biomarkers & Prevention. 3 (1): 67–71. ISSN 1055-9965. PMID 8118388.
  14. ^ Arneth, Borros (2018-05-04). "Update on the types and usage of liquid biopsies in the clinical setting: a systematic review". BMC Cancer. 18 (1): 527. doi:10.1186/s12885-018-4433-3. ISSN 1471-2407. PMC 5935950. PMID 29728089.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  15. ^ Babayan, Anna; Pantel, Klaus (2018-03-20). "Advances in liquid biopsy approaches for early detection and monitoring of cancer". Genome Medicine. 10 (1): 21. doi:10.1186/s13073-018-0533-6. ISSN 1756-994X. PMC 5861602. PMID 29558971.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  16. ^ Lood, Christian; Blanco, Luz P; Purmalek, Monica M; Carmona-Rivera, Carmelo; De Ravin, Suk S; Smith, Carolyne K; Malech, Harry L; Ledbetter, Jeffrey A; Elkon, Keith B (2016-2). "Neutrophil extracellular traps enriched in oxidized mitochondrial DNA are interferogenic and contribute to lupus-like disease". Nature Medicine. 22 (2): 146–153. doi:10.1038/nm.4027. ISSN 1078-8956. PMC 4742415. PMID 26779811. {{cite journal}}: Check date values in: |date= (help)CS1 maint: PMC format (link)
  17. ^ Yang, D.; Oyaizu, Y.; Oyaizu, H.; Olsen, G. J.; Woese, C. R. (1985-07-01). "Mitochondrial origins". Proceedings of the National Academy of Sciences. 82 (13): 4443–4447. doi:10.1073/pnas.82.13.4443. ISSN 0027-8424.
  18. ^ Zhang, Qin; Raoof, Mustafa; Chen, Yu; Sumi, Yuka; Sursal, Tolga; Junger, Wolfgang; Brohi, Karim; Itagaki, Kiyoshi; Hauser, Carl J. (2010-3). "Circulating mitochondrial DAMPs cause inflammatory responses to injury". Nature. 464 (7285): 104–107. doi:10.1038/nature08780. ISSN 0028-0836. PMC 2843437. PMID 20203610. {{cite journal}}: Check date values in: |date= (help)CS1 maint: PMC format (link)
  19. ^ a b Collins, L. Vincent; Hajizadeh, Shahin; Holme, Elisabeth; Jonsson, Ing-Marie; Tarkowski, Andrej (2004-6). "Endogenously oxidized mitochondrial DNA induces in vivo and in vitro inflammatory responses". Journal of Leukocyte Biology. 75 (6): 995–1000. doi:10.1189/jlb.0703328. {{cite journal}}: Check date values in: |date= (help)
  20. ^ Clayton, David A.; Doda, Jackie N.; Friedberg, Errol C. (1975), Hanawalt, Philip C.; Setlow, Richard B. (eds.), "Absence of a Pyrimidine Dimer Repair Mechanism for Mitochondrial DNA in Mouse and Human Cells", Molecular Mechanisms for Repair of DNA, Springer US, pp. 589–591, doi:10.1007/978-1-4684-2898-8_26, ISBN 9781468429008, retrieved 2019-04-30
  21. ^ Lood, Christian; Blanco, Luz P; Purmalek, Monica M; Carmona-Rivera, Carmelo; De Ravin, Suk S; Smith, Carolyne K; Malech, Harry L; Ledbetter, Jeffrey A; Elkon, Keith B (2016-2). "Neutrophil extracellular traps enriched in oxidized mitochondrial DNA are interferogenic and contribute to lupus-like disease". Nature Medicine. 22 (2): 146–153. doi:10.1038/nm.4027. ISSN 1078-8956. PMC 4742415. PMID 26779811. {{cite journal}}: Check date values in: |date= (help)CS1 maint: PMC format (link)
  22. ^ Shimada, Kenichi; Crother, Timothy R.; Karlin, Justin; Dagvadorj, Jargalsaikhan; Chiba, Norika; Chen, Shuang; Ramanujan, V. Krishnan; Wolf, Andrea J.; Vergnes, Laurent (2012-3). "Oxidized Mitochondrial DNA Activates the NLRP3 Inflammasome during Apoptosis". Immunity. 36 (3): 401–414. doi:10.1016/j.immuni.2012.01.009. PMC 3312986. PMID 22342844. {{cite journal}}: Check date values in: |date= (help); no-break space character in |first2= at position 8 (help); no-break space character in |first7= at position 3 (help); no-break space character in |first8= at position 7 (help)CS1 maint: PMC format (link)
  23. ^ West, A. Phillip; Khoury-Hanold, William; Staron, Matthew; Tal, Michal C.; Pineda, Cristiana M.; Lang, Sabine M.; Bestwick, Megan; Duguay, Brett A.; Raimundo, Nuno (2015-4). "Mitochondrial DNA stress primes the antiviral innate immune response". Nature. 520 (7548): 553–557. doi:10.1038/nature14156. ISSN 0028-0836. PMC 4409480. PMID 25642965. {{cite journal}}: Check date values in: |date= (help)CS1 maint: PMC format (link)
  24. ^ Lui, Yanni Y. N.; Chik, Ki-Wai; Chiu, Rossa W. K.; Ho, Cheong-Yip; Lam, Christopher W. K.; Lo, Y. M. Dennis (March 2002). "Predominant hematopoietic origin of cell-free DNA in plasma and serum after sex-mismatched bone marrow transplantation". Clinical Chemistry. 48 (3): 421–427. ISSN 0009-9147. PMID 11861434.
  25. ^ Page, Karen; Guttery, David S.; Zahra, Nathalie; Primrose, Lindsay; Elshaw, Shona R.; Pringle, J. Howard; Blighe, Kevin; Marchese, Stephanie D.; Hills, Allison (2013-10-18). "Influence of Plasma Processing on Recovery and Analysis of Circulating Nucleic Acids". PLoS ONE. 8 (10): e77963. doi:10.1371/journal.pone.0077963. ISSN 1932-6203. PMC 3799744. PMID 24205045.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  26. ^ Barták, Barbara Kinga; Kalmár, Alexandra; Galamb, Orsolya; Wichmann, Barnabás; Nagy, Zsófia Brigitta; Tulassay, Zsolt; Dank, Magdolna; Igaz, Péter; Molnár, Béla (2018-01-27). "Blood Collection and Cell-Free DNA Isolation Methods Influence the Sensitivity of Liquid Biopsy Analysis for Colorectal Cancer Detection". Pathology & Oncology Research. doi:10.1007/s12253-018-0382-z. ISSN 1219-4956. PMID 29374860.
  27. ^ Pérez-Barrios, Clara; Nieto-Alcolado, Irene; Torrente, María; Jiménez-Sánchez, Carolina; Calvo, Virginia; Gutierrez-Sanz, Lourdes; Palka, Magda; Donoso-Navarro, Encarnación; Provencio, Mariano (December 2016). "Comparison of methods for circulating cell-free DNA isolation using blood from cancer patients: impact on biomarker testing". Translational Lung Cancer Research. 5 (6): 665–672. doi:10.21037/tlcr.2016.12.03. ISSN 2218-6751. PMC 5233878. PMID 28149760.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  28. ^ Volik, Stanislav; Alcaide, Miguel; Morin, Ryan D.; Collins, Colin (2016-10-01). "Cell-free DNA (cfDNA): Clinical Significance and Utility in Cancer Shaped By Emerging Technologies". Molecular Cancer Research. 14 (10): 898–908. doi:10.1158/1541-7786.MCR-16-0044. ISSN 1541-7786. PMID 27422709.
  29. ^ Vasioukhin, V.; Anker, P.; Maurice, P.; Lyautey, J.; Lederrey, C.; Stroun, M. (April 1994). "Point mutations of the N-ras gene in the blood plasma DNA of patients with myelodysplastic syndrome or acute myelogenous leukaemia". British Journal of Haematology. 86 (4): 774–779. ISSN 0007-1048. PMID 7918071.
  30. ^ Forshew, Tim; Murtaza, Muhammed; Parkinson, Christine; Gale, Davina; Tsui, Dana W. Y.; Kaper, Fiona; Dawson, Sarah-Jane; Piskorz, Anna M.; Jimenez-Linan, Mercedes (2012-05-30). "Noninvasive Identification and Monitoring of Cancer Mutations by Targeted Deep Sequencing of Plasma DNA". Science Translational Medicine. 4 (136): 136ra68. doi:10.1126/scitranslmed.3003726. ISSN 1946-6234. PMID 22649089.
  31. ^ Newman, Aaron M.; Bratman, Scott V.; To, Jacqueline; Wynne, Jacob F.; Eclov, Neville C. W.; Modlin, Leslie A.; Liu, Chih Long; Neal, Joel W.; Wakelee, Heather A. (May 2014). "An ultrasensitive method for quantitating circulating tumor DNA with broad patient coverage". Nature Medicine. 20 (5): 548–554. doi:10.1038/nm.3519. ISSN 1546-170X. PMC 4016134. PMID 24705333.
  32. ^ Schwarzenbach, Heidi; Hoon, Dave S. B.; Pantel, Klaus (June 2011). "Cell-free nucleic acids as biomarkers in cancer patients". Nature Reviews. Cancer. 11 (6): 426–437. doi:10.1038/nrc3066. ISSN 1474-1768. PMID 21562580.
  33. ^ Lo, Y. M.; Rainer, T. H.; Chan, L. Y.; Hjelm, N. M.; Cocks, R. A. (March 2000). "Plasma DNA as a prognostic marker in trauma patients". Clinical Chemistry. 46 (3): 319–323. ISSN 0009-9147. PMID 10702517.
  34. ^ Chiu, Tor W.; Young, Richard; Chan, Lisa Y. S.; Burd, Andrew; Lo, Dennis Y. M. (2006). "Plasma cell-free DNA as an indicator of severity of injury in burn patients". Clinical Chemistry and Laboratory Medicine. 44 (1): 13–17. doi:10.1515/CCLM.2006.003. ISSN 1434-6621. PMID 16375578.
  35. ^ Rhodes, Andrew; Wort, Stephen J.; Thomas, Helen; Collinson, Paul; Bennett, E. David (2006). "Plasma DNA concentration as a predictor of mortality and sepsis in critically ill patients". Critical Care (London, England). 10 (2): R60. doi:10.1186/cc4894. ISSN 1466-609X. PMC 1550922. PMID 16613611.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  36. ^ Martins, G. A.; Kawamura, M. T.; Carvalho, M. da G. (April 2000). "Detection of DNA in the plasma of septic patients". Annals of the New York Academy of Sciences. 906: 134–140. ISSN 0077-8923. PMID 10818609.
  37. ^ Chang, Christine P.-Y.; Chia, Rhu-Hsin; Wu, Tsu-Lan; Tsao, Kuo-Chien; Sun, Chien-Feng; Wu, James T. (January 2003). "Elevated cell-free serum DNA detected in patients with myocardial infarction". Clinica Chimica Acta; International Journal of Clinical Chemistry. 327 (1–2): 95–101. ISSN 0009-8981. PMID 12482623.
  38. ^ Rainer, Timothy H.; Lam, Nicole Y. L.; Man, C. Y.; Chiu, Rossa W. K.; Woo, K. S.; Lo, Y. M. Dennis (June 2006). "Plasma beta-globin DNA as a prognostic marker in chest pain patients". Clinica Chimica Acta; International Journal of Clinical Chemistry. 368 (1–2): 110–113. doi:10.1016/j.cca.2005.12.021. ISSN 0009-8981. PMID 16480967.
  39. ^ a b Beck, J.; Oellerich, M.; Schulz, U.; Schauerte, V.; Reinhard, L.; Fuchs, U.; Knabbe, C.; Zittermann, A.; Olbricht, C. (October 2015). "Donor-Derived Cell-Free DNA Is a Novel Universal Biomarker for Allograft Rejection in Solid Organ Transplantation". Transplantation Proceedings. 47 (8): 2400–2403. doi:10.1016/j.transproceed.2015.08.035. ISSN 0041-1345. PMID 26518940.
  40. ^ Duvvuri, Bhargavi; Lood, Christian (2019-03-19). "Cell-Free DNA as a Biomarker in Autoimmune Rheumatic Diseases". Frontiers in Immunology. 10. doi:10.3389/fimmu.2019.00502. ISSN 1664-3224. PMC 6433826. PMID 30941136.{{cite journal}}: CS1 maint: PMC format (link) CS1 maint: unflagged free DOI (link)
  41. ^ Pinzani, Pamela; Salvianti, Francesca; Pazzagli, Mario; Orlando, Claudio (2010-4). "Circulating nucleic acids in cancer and pregnancy". Methods. 50 (4): 302–307. doi:10.1016/j.ymeth.2010.02.004. {{cite journal}}: Check date values in: |date= (help)
Retrieved from "https://en.wikipedia.org/w/index.php?title=Circulating_free_DNA&oldid=894915874"