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Tumor Biology |
Department of Biology [S. J., H. H., F. O. F., R. K.] and Steinbeis-Transfer-Laboratory for Biomolecular Medicine [S. E., R-D. H.], Universität Konstanz, D-78457 Konstanz, and Department of Oncology, Klinikum Konstanz [D. H.], D-78464, Konstanz, Germany
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ABSTRACT |
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 Top ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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INTRODUCTION |
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TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Because the issue of circulating DNA is not only of clinical relevance but also of considerable biological interest, we decided to investigate the origin of DNA in the plasma samples of 30 cancer patients of different tumor types. Using highly sensitive methods of quantitative PCR, we determined the fraction of DNA in the circulation that originates from tumor cells and from nontumor cells. We also sought for evidence showing that at least some of the DNA could be released from apoptotic or necrotic cells, a conclusion that we support by studies using cultured cells and mice with in vivo-induced apoptosis and necrosis.
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MATERIALS AND METHODS |
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TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Quantitation of Total Plasma DNA.
The amounts of plasma DNA were determined by competitive PCR according
to the method of Diviacco et al. (15)
, using
the lamin B2 locus as a typical example for a single copy gene. The
competitor molecule carrying a 20-bp insert was obtained directly from
two amplification products by the overlap extension method
(15)
. Quantitation of competitive templates was obtained
by OD260 measurement. For quantitation, a fixed
amount of plasma DNA was mixed with increasing amounts of the
competitor template. For competitive PCR, two additional primers (Q-EF:
5'-TCCAATGATTTGTAATATAC-3' and Q-ER: 5'-ATCTTTCTTAGACATCCGCTT-3') were
designed. After PCR amplification (40 cycles: 94°C, 1 min; 52°C, 1
min; 72°C, 1 min) and PAGE, two products of 153 and 173 bp were
evident, corresponding to genomic and competitor templates,
respectively. The ratios of the amplified products precisely reflect
the initial concentration of genomic DNA versus that of the
added competitor. Quantitation of competitor and genomic bands was
obtained by densitometric scanning of the ethidium bromide-stained gel
(15)
. The results obtained by means of competitive PCR
were confirmed by quantitation with the Control Kit DNA in the
LightCycler System (Roche Diagnostics). For that purpose we used the
LightCycler Control Kit DNA to amplify a 110-bp fragment of the human
ß-globin gene. The amplicon was detected by fluorescence using a
specific pair of hybridization probes (LC-Red 640). As standards
we used serially diluted genomic DNA of the kit. After completion of
PCR, the LightCycler software calculated the copy number of target
molecules by plotting logarithm of fluorescence versus cycle
number and setting a baseline x-axis. The concentrations of
the samples were extrapolated from the standard curve by the
LightCycler software.
T Cells.
The presence of T-cell DNA in plasma samples was examined by PCR
amplification of a region of the T-cell receptor ß chain,
which exhibits a somatic rearrangement by VDJ recombination
(16)
. For amplification, a mix of sense primers (Vßz5,
Vßz6) and one antisense primer (Jß1i) were used (16)
.
This leads to the amplification of DNA fragments with defined sizes:
907, 767, and 155 bp, depending on the rearranged Jß-segment.
DNA from Jurkat T cells, HeLa cells, and human lymphocytes was
included as internal controls with each run. As an additional control,
we amplified plasma DNA with primers specific for the germline
configuration of the T-cell receptor using the primers G1F:
5'-AATGATTCAACTCTACGGGA-3' (sense) and G1R: 5'-TGAGTCCTCCACTTGTGAG-3'
(antisense), resulting in a product of 250 bp. One hundred ng of
purified plasma DNA samples were used in each PCR assay. PCR products
were analyzed by 6% PAGE and ethidium bromide staining.
Hypermethylation of CDKN2A.
Detection of hypermethylated CpG islands in the promoter region of the
CDKN2A tumor suppressor gene was carried out by
methylation-specific PCR as previously described (17)
.
Bisulfite treatment of tumor or plasma DNA was carried out using the
CpGenome DNA modification kit (Intergen). As a positive control, normal
human dermal fibroblast cell DNA was methylated in
vitro using the CpG methylase (New England BioLabs). PCR products
were analyzed after electrophoresis on 6% polyacrylamide gels.
Quantitation of Hypermethylated CDKN2A.
The ratio between unmethylated and hypermethylated CDKN2A
alleles in plasma of cancer patients was analyzed using
methylation-specific quantification in the LightCycler system (Roche
Diagnostics). For amplification of unmethylated DNA, we used primers
according to Herman et al. (17)
. For the
methylated CDNK2A, the following set of PCR primers was
used: 5'-GGTGGGGCGGATCGC-3' (sense) and 5'-CCGAACCGCGACCGTAA-3'
(antisense). Two sets of LC-Red 640-labeled, methylation-specific
hybridization probes were used for detection of real-time PCR products
in the LightCycler reaction: for the unmethylated reaction
5'-CTCCCCACCACCCACTACCTACTCT-3' (p16N FL) and
5'-CCCCTCTCCACAACCACCAAACAC-3' (p16N LC) and for the methylated
reaction 5'-CCGCCGCCCGCTACCTACTCT-3' (p16M FL) and
5'-CCTCTCCGCAACCGCCGAAC-3' (p16M LC). PCR (40 cycles of denaturation
for 10 s at 95°C, annealing for 10 s at 69°C, and
extension for 10 s at 72°C) was performed with the LightCycler
FastStart DNA Master Hybridization Probes Kit (Roche Diagnostics). A
fixed volume of 4 µl deaminated plasma DNA was applied in each PCR
assay. In vitro methylated DNA and DNA from normal human
lymphocytes were used as standard DNA for the quantitation of
methylated and unmethylated CDKN2A, respectively. The
efficiency of the in vitro methylation of the standard DNA
was analyzed by real-time PCR before quantitations: in the unmethylated
CDKN2A reaction no product was visible using this in
vitro methylated DNA as template. For all of the assays the same
standard DNA was used. The methylation-specific measurements of plasma
DNA were all performed in duplicates. The difference between the
samples in each LightCycler assay was about ±10% for both
unmethylated and methylated DNA.
Endothelial Cells.
To investigate the presence of endothelial cell DNA in the plasma, a
methylation-specific PCR-based method was established. After bisulfite
treatment of purified plasma DNA (CpGenome Modification Kit;
Intergene), a methylation-specific PCR in the promoter region of
the selectin E (SELE) gene was carried
out. Two different sets of primers were used to distinguish the
unmethylated from the hypermethylated SELE promoter:
unmethylated: 5'-ATTTTAAGTATTGTGGATATTTTTG-3' (sense) and
5'-CAAAAACAACTAAACACTACTTCA-3' (antisense); hypermethylated:
5'-TTTAAGTATCGTGGATATTTTCG-3' (sense) and
5'-AAAAACAACTAAACACTACTTCG-3' (antisense). The sequence-specific
primers cover three CpG islands, two of which are positioned at the 3'
end of the primers. Thirty-five PCR cycles were performed, with each
cycle consisting of 1 min at 94°C, 1 min at 50°C, and 1 min at
72°C. DNA of HeLa cells and of
HUVECs3
served as negative and positive controls, respectively. PCR products
(151 bp) were visualized after electrophoresis on 6% polyacrylamide
gels and ethidium bromide staining.
Induction of Apoptosis and Necrosis in Vitro.
Jurkat T cells in serum-free medium without glucose were induced to
undergo necrosis (with 2.5 µM oligomycin plus 1.2
µM staurosporine) or apoptosis (with 1.2 µM
staurosporine) as previously described (18)
. At different
times after the addition of drugs, the supernatant was separated from
the cells by centrifugation. The DNA of the supernatants was purified
(QIAamp blood kit; Qiagen) and quantified by competitive PCR. Apoptotic
and necrotic cell death were confirmed by monitoring the cleavage of
the nuclear SAF-A in Western blot analyses. Only during apoptotic, but
not necrotic cell death, is SAF-A cleaved by caspase-3 (19
, 20) .
Induction of Apoptotic and Necrotic Liver Injury in Mice.
Specific pathogen-free male BALB/c mice (
25 g, from the in-house
animal breeding station of the University of Konstanz) were maintained
under controlled conditions (22°C and 55% humidity, constant 12-h
day/night cycle) and fed a standard laboratory chow. All animals
received humane care in accordance with the NIH guidelines as well as
with the legal requirements in Germany. Mice were starved overnight
before the onset of experiments. To induce hepatocyte apoptosis,
activating anti-CD95 antibody (
CD95, clone Jo-2, 2 µg per animal;
PharMingen) was injected i.v. in a volume of 300 µl endotoxin-free
saline supplemented with 0.1% human serum albumin (21
, 22)
. Hepatocyte necrosis was induced by i.p. treatment of mice
with acetaminophen (250 mg/kg in 300 µl endotoxin-free saline; EGA,
Steinheim, Germany; Ref. 20
). At the time points
indicated, mice were killed by i.v. injection of 150 mg/kg
pentobarbital plus 1.2 mg/kg sodium citrate as an anticoagulant. Blood
was withdrawn by cardiac puncture and centrifuged (5 min,
14,000 x g, 4°C) to obtain plasma. The
extent of liver damage was assessed by measuring plasma ALT activity
with an EPOS 5060 analyzer (Netheler & Hintz, Hamburg, Germany)
as previously described (23)
. DNA was extracted from
murine plasma using a DNA extraction kit (QIAamp blood kit; Qiagen) and
quantified by real-time PCR (LightCycler; Roche Diagnostics). The
region of amplification was part of exon 3 of the murine -actin
gene. The following primers were used for amplification:
5'-TGAACATGGCATCATCACC-3' and 5'-CTGGATAGCCACATACATG-3', resulting in a
product of 199 bp. Real-time quantitation was carried out by the
SYBR-Green reaction mix (Roche Diagnostics). A fixed amount of 4 µl
of eluted DNA was used in each PCR reaction. Forty PCR cycles were
performed, with each cycle consisting of 1 s at 95°C, 5 s
at 55°C, and 10 s at 72°C.
Analysis of Plasma DNA Fragments.
DNA of human or murine plasma was extracted using a DNA extraction kit
(QIAamp blood kit; Qiagen) and separated on 6% polyacrylamide gels
(patients’ plasma DNA samples) or 1.5% agarose gels (murine plasma
DNA samples). Fragments were then visualized after ethidium bromide
staining.
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RESULTS |
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TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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. For that purpose, we used primers corresponding to a subtelomeric
single-copy region of chromosome 19 in the quantitative PCR procedure
of Diviacco et al. (15)
. The data obtained by
quantitative PCR were verified by real-time quantitation in a
LightCycler instrument (Roche Diagnostics). The difference between the
results obtained by these two methods was ±13%. All quantitations
were performed in duplicate, with a reproducibility of ±12.5% in the
competitive assays and ±10% in the LightCycler assays. The results of
quantitation revealed a wide spectrum of DNA concentrations in the
plasma of cancer patients, between 10 and 1200 ng/ml, with a mean of
219 ng/ml (Fig. 1)
. We observed no clear correlation between the concentrations of DNA in
the plasma and the clinical situation such as diagnosis, tumor staging,
or therapy, e.g., advanced pancreatic adenocarcinoma was
diagnosed in patients C20 and C14, yet patient C20 had the relatively
low concentration of 48 ng DNA/ml plasma, whereas patient C14 had the
highest plasma DNA concentration (1200 ng/ml; Fig. 1
; Table 1
). In
fact, some of the values in the group of cancer patients were not
higher than the DNA concentrations determined in the plasma of two
persons in the control group (mean, 3.7 ng DNA/ml plasma; highest
values, 10–15 ng/ml). However, most of the control cases had <2 ng/ml
DNA in their plasma (Fig. 1)
, which is at the limit of sensitivity of
the competitive assays. Thus, we conclude that elevated levels of
circulating DNA appear to be a characteristic feature of most, but not
all of the carcinoma diseases.
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. In control experiments, the T-cell-specific primers
amplified the clonal rearranged genomic sequence in the Jurkat T-cell
line (Fig. 2B
, Lane J) and in WBCs (Fig. 2B
, Lane B) but gave negative results with HeLa
DNA (Fig. 2B
, Lane H). Conversely, primers
specific for the germline configuration amplified the expected sequence
in HeLa cell DNA and WBC DNA, but not in Jurkat cell DNA (Fig. 2C
, Lanes H, J, and B).
Using these primers, we detected mature T-cell DNA sequences in the
plasma DNA samples C14 (pancreatic adenocarcinoma, 1200 ng DNA/ml
plasma; Fig. 2B
) and T5 (stomach cancer, 500 ng/ml), whereas
all of the other plasma DNA samples examined were devoid of detectable
T-cell DNA (Table 1)
. All of the plasma samples of cancer patients
examined gave positive results with the germline PCR (Fig. 2C)
. This result leads to the conclusion that DNA in the
circulation of cancer patients does not very frequently contain
T-lymphocyte DNA.
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), a percentage that is in agreement with published
studies (26, 27, 28, 29, 30, 31, 32)
. In the six cases in which both plasma
and tumor tissue were available, the results of the
methylation-specific PCR were identical in corresponding plasma and
tissue samples. Most of the positive plasma DNA samples contained DNA
with both methylated and unmethylated CDKN2A-promoter
sequences. As mentioned, the clear differentiation between unmethylated
nontumor and methylated tumor DNA segments in the same plasma DNA
sample allows a real-time PCR quantitation by the LightCycler
technology (Fig. 3A)
. The results of six experiments are shown in Fig. 3B
and reveal that the fraction of DNA with hypermethylated
CDKN2A-promoter sequences varies from >90% (sample C10) to
<10% (sample 23). Interestingly, samples with a high percentage of
tumor-specific hypermethylated DNA tend to belong to a group with lower
than average concentrations of circulating DNA: C10 (from a breast
cancer patient with 20 ng DNA/ml plasma), C2 (angiosarcoma patient with
only 19 ng DNA/ml), and C13 (melanoma patient with 20 ng DNA/ml plasma;
Fig. 3B
; Table 1
). In contrast, sample C23 (breast cancer)
has <10% tumor-specific hypermethylated DNA in a total of 360 ng
DNA/ml plasma.
|
. Following the reasoning explained above, we found the
gene promoter unmethylated in a HUVEC line and hypermethylated in human
HeLa cells and HL60 cells (Fig. 4B)
. Using the same PCR
procedure for an investigation of surgically removed tumor tissue, we
always detected a small fraction of unmethylated DNA in the presence of
a much larger fraction of methylated SELE gene promoter DNA
(Fig. 4C)
. This was expected, because endothelial cells
constitute a small fraction of the cells in a surgical preparation. In
contrast to DNA from tumor tissue, we found no evidence for
unmethylated C8, C11, C14, C23, T2, T3, T6, and T7 (Fig. 4C
;
Table 1
). We, therefore, conclude that very little, if any, DNA in the
plasma DNA samples of cancer patients derives from the degeneration of
endothelial cells.
|
180
bp, sometimes accompanied by DNA fragments two, three, or four times
this size (Fig. 5A
; patients C7, T5, and T6). We also detected
high-molecular-weight DNA fragments in some samples (Fig. 5, A and B
; patients C4 and C9). Plasma DNA of
patient C14 consisted of both types of fragment sizes. The spectrum of
multiples of 180-bp fragments is reminiscent of the oligonucleosomal
DNA ladder characteristic for apoptotic cell death when cellular
chromatin is degraded by a caspase-activated DNase (35)
.
On the other hand, DNA fragments larger than 10,000 bp could
originate from cells dying via necrosis.
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, chromatin began to appear in the supernatant 3 h
after induction of both necrosis or apoptosis.
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CD95
and acetaminophen, respectively (21
, 22
, 37)
. As shown in
Fig. 6B
(left), we could detect a dramatic increase of DNA
in plasma of mice treated with CD95. The appearance of plasma DNA
4 h after induction of apoptosis paralleled the increase in plasma
ALT activity, which reached a maximum after 8 h (2,790 IU
ALT). Furthermore, the sizes of DNA fragments in the plasma
corresponded to mono- and dinucleosomal DNA (Fig. 6B
,
right). The results of plasma DNA quantitation of mice after treatment
with acetaminophen is shown in Fig. 6C
(left). The increase
of plasma DNA occurred with similar kinetics and was even more
dramatic compared with the apoptosis model, reaching levels of >150
µg/ml plasma 6 h after treatment of mice. At this time point,
the extent of liver injury was maximal, as expressed by a plasma ALT
level of 2200 IU ALT. In contrast to the mono- and dinucleosomal DNA
fragments appearing in the plasma of CD95-treated mice, we here
found a time-dependent increase of DNA fragments >10,000 bp, as
expected for necrotic cell death (Fig. 6C
, right). These
results support the idea that the DNA in the circulation of cancer
patients could originate from both apoptotic and necrotic cells in
cancer tissue and that a discrimination of DNA originating from either
type of cell death is possible by the determination of DNA size
distribution. |
DISCUSSION |
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TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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Plasma DNA can originate from both tumor and nontumor cells. We found that neither T cells nor endothelial cells seem to contribute to plasma levels of DNA, with the exception of two cancer patients who had T-cell DNA in their plasma samples. We conclude that the nontumor DNA in human plasma originates from other cells surrounding the tumor tissue that are degenerated by the growing tumor (38) . To determine the ratio of tumor and nontumor DNA, we measured the hypermethylation of the CDKN2A gene promoter, an epigenetic DNA modification that is characteristic for the DNA in many cancer cell types (27) . We could detect hypermethylation in >40% of the samples studied, a value that agrees well with reports in the literature (26, 27, 28, 29, 30, 31, 32) . Quantities of hypermethylated tumor-derived DNA and unmethylated DNA from nontumor cells were determined by parallel quantitative methylation-specific PCR assays, showing that some samples of plasma DNA consisted of a high proportion of tumor cell DNA, whereas others consisted predominantly of DNA from nontumor cells. A case in point are samples C10, C8, and C23, which were all taken from advanced breast cancer patients with metastases but show different percentages of tumor-derived DNA. We estimate, however, that the absolute amounts of tumor-derived DNA are similar, ranging from 7 to 18 ng/ml plasma. In fact, in the six cases that we have studied, the concentration of tumor-derived DNA is generally low: <20 ng/ml, with a range of 5 to 18 ng/ml. Studies from other laboratories have investigated microsatellite loss of heterozygosity in plasma DNA and concluded that in at least some cancer patients nearly the whole plasma DNA is derived from the tumor cells (7 , 9) . This contrasts with other studies that detected wild-type DNA in the plasma of nearly all of the cancer patients (13) . In fact, many studies had to use very sensitive methods such as mutant allele-specific PCR (MASA) or RFLP PCR to detect mutations in plasma DNA samples of cancer patients (6 , 39) . Here we describe that the fraction of tumor-derived DNA appears to be higher when the total level of plasma DNA is low. This could lead to the conclusion that the fraction of tumor DNA in plasma may be correlated with the state of tumor progression: small tumors shed small amounts of DNA; larger tumors that infiltrate the surrounding normal tissue shed more DNA including that from adjacent nontumor cells. However, the data presented here do not seem to support this possibility, because similar clinical situations are associated with widely differing amounts of circulating tumor as well as nontumor DNA levels. Although a larger and more systematic study is necessary to decide this issue, it appears that although cancer does usually lead to an increase of plasma DNA, its amount and composition varies between patients. This may not be surprising given the multitude of reactions that are expected to occur from the time when DNA is released from degenerating cells until its eventual appearance in the circulation.
Our studies with cell cultures and animal models show that soluble DNA in the form of chromatin fragments are released from apoptotic and necrotic cells and can eventually appear in the blood stream. We, therefore, assume that the source of DNA in the blood plasma of cancer patients are cells that disintegrate by apoptosis and/or necrosis in expanding tumor tissue. It is possible to distinguish between the two models of cell death: apoptosis produces DNA fragments of 180 bp (and multiples of this), whereas necrosis results in much larger fragments. Both types of fragment sizes are found in the blood stream of cancer patients. In some of the analyzed cancer patients we found no evidence for apoptotic DNA. In fact, necrosis of tumor cells has been postulated to be the origin of plasma DNA in cancer patients in a number of earlier studies (2, 3, 4 , 13) , including one study that showed an increase of plasma DNA after radiation therapy (40) . However, we have shown here that apoptosis of cancer cells is at least as likely to lead to increased plasma DNA levels.
As a conclusion, we envisage the following scenario. As the size of a tumor increases, vascularization becomes a problem, causing hypoxia in regions remote from blood vessels. Hypoxia induces p53-dependent or p53-independent apoptosis of tumor cells and of nontumor cells in the infiltrated tissues (41) , just as cells may die by necrosis. Dead cells are normally removed by phagocytes (36 , 42) , but this process may not be efficient in and around tumors, or some fraction of the released soluble chromatin fragments may escape clearance by phagocytes and find its way into the blood stream. Clearly, several complex processes determine the fate of the DNA released from degenerating cells in tumor tissue, and it can be expected that the efficiencies of these processes depend on many variables. This may explain the large variation in the amounts and composition of DNA found in the circulation of cancer patients.
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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1 Supported by Deutsche Forschungsgemeinschaft. 
2 To whom requests for reprints should be
addressed, at the Department of Biology, Universität Konstanz,
Universitätsstr. 10, D-78457 Konstanz, Germany. E-mail: Sabine.Jahr{at}web.de
3 The abbreviations used are: HUVEC, human
vascular endothelial cell; SAF, scaffold attachment factor; ALT,
alanine aminotransferase.
Received 6/12/00. Accepted 12/ 7/00.
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REFERENCES |
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TopABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
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B transactivation. Biochem. Biophys. Res. Commun., 194: 215-221, 1993.[Medline]
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 F. Banki, R. J. Mason, D. Oh, J. A. Hagen, S. R. DeMeester, J. C. Lipham, K. Tanaka, K. D. Danenberg, W. N. Yacoub, P. V. Danenberg, et al. Plasma DNA as a Molecular Marker for Completeness of Resection and Recurrent Disease in Patients With Esophageal Cancer Arch Surg, June 1, 2007; 142(6): 533 - 539. [Abstract] [Full Text] [PDF]
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S. Urakami, H. Shiina, H. Enokida, H. Hirata, K. Kawamoto, T. Kawakami, N. Kikuno, Y. Tanaka, S. Majid, M. Nakagawa, et al. Wnt Antagonist Family Genes as Biomarkers for Diagnosis, Staging, and Prognosis of Renal Cell Carcinoma Using Tumor and Serum DNA Clin. Cancer Res., December 1, 2006; 12(23): 6989 - 6997. [Abstract] [Full Text] [PDF]
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 M. L. Bajt, C. Cover, J. J. Lemasters, and H. Jaeschke Nuclear Translocation of Endonuclease G and Apoptosis-Inducing Factor during Acetaminophen-Induced Liver Cell Injury Toxicol. Sci., November 1, 2006; 94(1): 217 - 225. [Abstract] [Full Text] [PDF]
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N. Umetani, A. E. Giuliano, S. H. Hiramatsu, F. Amersi, T. Nakagawa, S. Martino, and D. S.B. Hoon Prediction of Breast Tumor Progression by Integrity of Free Circulating DNA in Serum J. Clin. Oncol., September 10, 2006; 24(26): 4270 - 4276. [Abstract] [Full Text] [PDF]
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I. G. Fatouros, A. Destouni, K. Margonis, A. Z. Jamurtas, C. Vrettou, D. Kouretas, G. Mastorakos, A. Mitrakou, K. Taxildaris, E. Kanavakis, et al. Cell-Free Plasma DNA as a Novel Marker of Aseptic Inflammation Severity Related to Exercise Overtraining Clin. Chem., September 1, 2006; 52(9): 1820 - 1824. [Abstract] [Full Text] [PDF]
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 N. Hagiwara, L. E. Mechanic, G. E. Trivers, H. L. Cawley, M. Taga, E. D. Bowman, K. Kumamoto, P. He, M. Bernard, S. Doja, et al. Quantitative Detection of p53 Mutations in Plasma DNA from Tobacco Smokers Cancer Res., August 15, 2006; 66(16): 8309 - 8317. [Abstract] [Full Text] [PDF]
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K. Koyanagi, T. Mori, S. J. O'Day, S. R. Martinez, H.-J. Wang, and D. S.B. Hoon Association of circulating tumor cells with serum tumor-related methylated DNA in peripheral blood of melanoma patients. Cancer Res., June 15, 2006; 66(12): 6111 - 6117. [Abstract] [Full Text] [PDF]
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N. Umetani, J. Kim, S. Hiramatsu, H. A. Reber, O. J. Hines, A. J. Bilchik, and D. S. B. Hoon Increased Integrity of Free Circulating DNA in Sera of Patients with Colorectal or Periampullary Cancer: Direct Quantitative PCR for ALU Repeats. Clin. Chem., June 1, 2006; 52(6): 1062 - 1069. [Abstract] [Full Text] [PDF]
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N. J. Park, Y. Li, T. Yu, B. M.N. Brinkman, and D. T. Wong Characterization of RNA in Saliva Clin. Chem., June 1, 2006; 52(6): 988 - 994. [Abstract] [Full Text] [PDF]
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Y. Li, D. Elashoff, M. Oh, U. Sinha, M. A.R. St John, X. Zhou, E. Abemayor, and D. T. Wong Serum Circulating Human mRNA Profiling and Its Utility for Oral Cancer Detection J. Clin. Oncol., April 10, 2006; 24(11): 1754 - 1760. [Abstract] [Full Text] [PDF]
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 J. Li, L. Harris, H. Mamon, M. H. Kulke, W.-H. Liu, P. Zhu, and G. Mike Makrigiorgos Whole Genome Amplification of Plasma-Circulating DNA Enables Expanded Screening for Allelic Imbalance in Plasma J. Mol. Diagn., February 1, 2006; 8(1): 22 - 30. [Abstract] [Full Text] [PDF]
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H. Jaeschke and M. L. Bajt Intracellular Signaling Mechanisms of Acetaminophen-Induced Liver Cell Death Toxicol. Sci., January 1, 2006; 89(1): 31 - 41. [Abstract] [Full Text] [PDF]
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 G. Sozzi, L. Roz, D. Conte, L. Mariani, F. Andriani, P. Verderio, and U. Pastorino Effects of Prolonged Storage of Whole Plasma or Isolated Plasma DNA on the Results of Circulating DNA Quantification Assays J Natl Cancer Inst, December 21, 2005; 97(24): 1848 - 1850. [Abstract] [Full Text] [PDF]
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F. Diehl, M. Li, D. Dressman, Y. He, D. Shen, S. Szabo, L. A. Diaz Jr, S. N. Goodman, K. A. David, H. Juhl, et al. Detection and quantification of mutations in the plasma of patients with colorectal tumors PNAS, November 8, 2005; 102(45): 16368 - 16373. [Abstract] [Full Text] [PDF]
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 C. Cover, A. Mansouri, T. R. Knight, M. L. Bajt, J. J. Lemasters, D. Pessayre, and H. Jaeschke Peroxynitrite-Induced Mitochondrial and Endonuclease-Mediated Nuclear DNA Damage in Acetaminophen Hepatotoxicity J. Pharmacol. Exp. Ther., November 1, 2005; 315(2): 879 - 887. [Abstract] [Full Text] [PDF]
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 M. V. Brock, C. M. Hooker, R. Yung, M. Guo, Y. Han, S. E. Ames, D. Chang, S. C. Yang, D. Mason, M. Sussman, et al. Can We Improve the Cytologic Examination of Malignant Pleural Effusions Using Molecular Analysis? Ann. Thorac. Surg., October 1, 2005; 80(4): 1241 - 1247. [Abstract] [Full Text] [PDF]
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S. Holdenrieder, P. Stieber, L. Y.S. Chan, S. Geiger, A. Kremer, D. Nagel, and Y.M. D. Lo Cell-Free DNA in Serum and Plasma: Comparison of ELISA and Quantitative PCR Clin. Chem., August 1, 2005; 51(8): 1544 - 1546. [Full Text] [PDF]
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S. N. Tamkovich, O. E. Bryzgunova, E. Yu. Rykova, V. I. Permyakova, V. V. Vlassov, and P. P. Laktionov Circulating Nucleic Acids in Blood of Healthy Male and Female Donors Clin. Chem., July 1, 2005; 51(7): 1317 - 1319. [Full Text] [PDF]
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 L. A. Trouw, S. C. Nilsson, I. Goncalves, G. Landberg, and A. M. Blom C4b-binding protein binds to necrotic cells and DNA, limiting DNA release and inhibiting complement activation J. Exp. Med., June 20, 2005; 201(12): 1937 - 1948. [Abstract] [Full Text] [PDF]
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 K. Miyamoto and T. Ushijima Diagnostic and Therapeutic Applications of Epigenetics Jpn. J. Clin. Oncol., June 1, 2005; 35(6): 293 - 301. [Abstract] [Full Text] [PDF]
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P. B. Larrabee, K. L. Johnson, I. Peter, and D. W. Bianchi Presence of Filterable and Nonfilterable Cell-Free mRNA in Amniotic Fluid Clin. Chem., June 1, 2005; 51(6): 1024 - 1026. [Full Text] [PDF]
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P. J. Bastian, G. S. Palapattu, X. Lin, S. Yegnasubramanian, L. A. Mangold, B. Trock, M. A. Eisenberger, A. W. Partin, and W. G. Nelson Preoperative Serum DNA GSTP1 CpG Island Hypermethylation and the Risk of Early Prostate-Specific Antigen Recurrence Following Radical Prostatectomy Clin. Cancer Res., June 1, 2005; 11(11): 4037 - 4043. [Abstract] [Full Text] [PDF]
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 N. Jiang and D. S. Pisetsky The effect of inflammation on the generation of plasma DNA from dead and dying cells in the peritoneum J. Leukoc. Biol., March 1, 2005; 77(3): 296 - 302. [Abstract] [Full Text] [PDF]
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C. Cover, P. Fickert, T. R. Knight, A. Fuchsbichler, A. Farhood, M. Trauner, and H. Jaeschke Pathophysiological Role of Poly(ADP-Ribose) Polymerase (PARP) Activation during Acetaminophen-Induced Liver Cell Necrosis in Mice Toxicol. Sci., March 1, 2005; 84(1): 201 - 208. [Abstract] [Full Text] [PDF]
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T. R. Gingeras, R. Higuchi, L. J. Kricka, Y.M. D. Lo, and C. T. Wittwer Fifty Years of Molecular (DNA/RNA) Diagnostics Clin. Chem., March 1, 2005; 51(3): 661 - 671. [Full Text] [PDF]
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J. L. Boddy, S. Gal, P. R. Malone, A. L. Harris, and J. S. Wainscoat Prospective Study of Quantitation of Plasma DNA Levels in the Diagnosis of Malignant versus Benign Prostate Disease Clin. Cancer Res., February 15, 2005; 11(4): 1394 - 1399. [Abstract] [Full Text] [PDF]
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F. Z. Bischoff, D. E. Lewis, and J. L. Simpson Cell-free fetal DNA in maternal blood: kinetics, source and structure Hum. Reprod. Update, January 1, 2005; 11(1): 59 - 67. [Abstract] [Full Text] [PDF]
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L. J. Herrera, S. Raja, W. E. Gooding, T. El-Hefnawy, L. Kelly, J. D. Luketich, and T. E. Godfrey Quantitative Analysis of Circulating Plasma DNA as a Tumor Marker in Thoracic Malignancies Clin. Chem., January 1, 2005; 51(1): 113 - 118. [Abstract] [Full Text] [PDF]
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S. Holdenrieder, P. Stieber, J. von Pawel, H. Raith, D. Nagel, K. Feldmann, and D. Seidel Circulating Nucleosomes Predict the Response to Chemotherapy in Patients with Advanced Non-Small Cell Lung Cancer Clin. Cancer Res., September 15, 2004; 10(18): 5981 - 5987. [Abstract] [Full Text] [PDF]
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 A M Gilbey, D Burnett, R E Coleman, and I Holen The detection of circulating breast cancer cells in blood J. Clin. Pathol., September 1, 2004; 57(9): 903 - 911. [Abstract] [Full Text] [PDF]
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V. M. M. van Houten, C. R. Leemans, J. A. Kummer, J. Dijkstra, D. J. Kuik, M. W. M. van den Brekel, G. B. Snow, and R. H. Brakenhoff Molecular Diagnosis of Surgical Margins and Local Recurrence in Head and Neck Cancer Patients: A Prospective Study Clin. Cancer Res., June 1, 2004; 10(11): 3614 - 3620. [Abstract] [Full Text] [PDF]
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Y.-H. Su, M. Wang, D. E. Brenner, A. Ng, H. Melkonyan, S. Umansky, S. Syngal, and T. M. Block Human Urine Contains Small, 150 to 250 Nucleotide-Sized, Soluble DNA Derived from the Circulation and May Be Useful in the Detection of Colorectal Cancer J. Mol. Diagn., May 1, 2004; 6(2): 101 - 107. [Abstract] [Full Text] [PDF]
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 N. Jiang and D. S. Pisetsky The Effect of Dexamethasone on the Generation of Plasma DNA from Dead and Dying Cells Am. J. Pathol., May 1, 2004; 164(5): 1751 - 1759. [Abstract] [Full Text] [PDF]
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T.-S. Wong, D. L.-W. Kwong, J. S.-T. Sham, W. I. Wei, Y.-L. Kwong, and A. P.-W. Yuen Quantitative Plasma Hypermethylated DNA Markers of Undifferentiated Nasopharyngeal Carcinoma Clin. Cancer Res., April 1, 2004; 10(7): 2401 - 2406. [Abstract] [Full Text] [PDF]
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 S. E. Cottrell, J. Distler, N. S. Goodman, S. H. Mooney, A. Kluth, A. Olek, I. Schwope, R. Tetzner, H. Ziebarth, and K. Berlin A real-time PCR assay for DNA-methylation using methylation-specific blockers Nucleic Acids Res., January 13, 2004; 32(1): e10 - e10. [Abstract] [Full Text] [PDF]
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K.C. A. Chan, J. Zhang, A. B.Y. Hui, N. Wong, T. K. Lau, T. N. Leung, K.-W. Lo, D. W.S. Huang, and Y.M. D. Lo Size Distributions of Maternal and Fetal DNA in Maternal Plasma Clin. Chem., January 1, 2004; 50(1): 88 - 92. [Abstract] [Full Text] [PDF]
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M. Wang, T. M. Block, L. Steel, D. E. Brenner, and Y.-H. Su Preferential Isolation of Fragmented DNA Enhances the Detection of Circulating Mutated k-ras DNA Clin. Chem., January 1, 2004; 50(1): 211 - 213. [Full Text] [PDF]
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N. Y.L. Lam, T. H. Rainer, L. Y.S. Chan, G. M. Joynt, and Y.M. D. Lo Time Course of Early and Late Changes in Plasma DNA in Trauma Patients Clin. Chem., August 1, 2003; 49(8): 1286 - 1291. [Abstract] [Full Text] [PDF]
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B. G. Wang, H.-Y. Huang, Y.-C. Chen, R. E. Bristow, K. Kassauei, C.-C. Cheng, R. Roden, L. J. Sokoll, D. W. Chan, and I.-M. Shih Increased Plasma DNA Integrity in Cancer Patients Cancer Res., July 15, 2003; 63(14): 3966 - 3968. [Abstract] [Full Text] [PDF]
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K.C. A. Chan, J. Zhang, A. T.C. Chan, K. I.K. Lei, S.-F. Leung, L. Y.S. Chan, K. C.K. Chow, and Y.M. D. Lo Molecular Characterization of Circulating EBV DNA in the Plasma of Nasopharyngeal Carcinoma and Lymphoma Patients Cancer Res., May 1, 2003; 63(9): 2028 - 2032. [Abstract] [Full Text] [PDF]
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R. W.K. Chiu, L. Y.S. Chan, N. Y.L. Lam, N. B.Y. Tsui, E. K.O. Ng, T. H. Rainer, and Y.M. D. Lo Quantitative Analysis of Circulating Mitochondrial DNA in Plasma Clin. Chem., May 1, 2003; 49(5): 719 - 726. [Abstract] [Full Text] [PDF]
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C. Balana, J. L. Ramirez, M. Taron, Y. Roussos, A. Ariza, R. Ballester, C. Sarries, P. Mendez, J. J. Sanchez, and R. Rosell O6-methyl-guanine-DNA methyltransferase Methylation in Serum and Tumor DNA Predicts Response to 1,3-Bis(2-Chloroethyl)-1-Nitrosourea but not to Temozolamide Plus Cisplatin in Glioblastoma Multiforme Clin. Cancer Res., April 1, 2003; 9(4): 1461 - 1468. [Abstract] [Full Text] [PDF]
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I. H. N. Wong, J. Zhang, P. B. S. Lai, W. Y. Lau, and Y. M. Dennis Lo Quantitative Analysis of Tumor-derived Methylated p16INK4a Sequences in Plasma, Serum, and Blood Cells of Hepatocellular Carcinoma Patients Clin. Cancer Res., March 1, 2003; 9(3): 1047 - 1052. [Abstract] [Full Text] [PDF]
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H.-W. Chang, S. M. Lee, S. N. Goodman, G. Singer, S. K. R. Cho, L. J. Sokoll, F. J. Montz, R. Roden, Z. Zhang, D. W. Chan, et al. Assessment of Plasma DNA Levels, Allelic Imbalance, and CA 125 as Diagnostic Tests for Cancer J Natl Cancer Inst, November 20, 2002; 94(22): 1697 - 1703. [Abstract] [Full Text] [PDF]
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E. K.O. Ng, N. B.Y. Tsui, N. Y.L. Lam, R. W.K. Chiu, S. C.H. Yu, S.C. C. Wong, E. S.F. Lo, T. H. Rainer, P. J. Johnson, and Y.M. D. Lo Presence of Filterable and Nonfilterable mRNA in the Plasma of Cancer Patients and Healthy Individuals Clin. Chem., August 1, 2002; 48(8): 1212 - 1217. [Abstract] [Full Text] [PDF]
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H.-W. Chang, S. Z. Ali, S. K. R. Cho, R. J. Kurman, and I.-M. Shih Detection of Allelic Imbalance in Ascitic Supernatant by Digital Single Nucleotide Polymorphism Analysis Clin. Cancer Res., August 1, 2002; 8(8): 2580 - 2585. [Abstract] [Full Text] [PDF]
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J. S. Gujral, T. R. Knight, A. Farhood, M. L. Bajt, and H. Jaeschke Mode of Cell Death after Acetaminophen Overdose in Mice: Apoptosis or Oncotic Necrosis? Toxicol. Sci., June 1, 2002; 67(2): 322 - 328. [Abstract] [Full Text] [PDF]
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H.-Z. Zou, B.-M. Yu, Z.-W. Wang, J.-Y. Sun, H. Cang, F. Gao, D. H. Li, R. Zhao, G.-G. Feng, and J. Yi Detection of Aberrant p16 Methylation in the Serum of Colorectal Cancer Patients Clin. Cancer Res., January 1, 2002; 8(1): 188 - 191. [Abstract] [Full Text] [PDF]
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R. W. K. Chiu, L. L. M. Poon, T. K. Lau, T. N. Leung, E. M. C. Wong, and Y. M. D. Lo Effects of Blood-Processing Protocols on Fetal and Total DNA Quantification in Maternal Plasma Clin. Chem., September 1, 2001; 47(9): 1607 - 1613. [Abstract] [Full Text] [PDF]
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D. O. Hasselmann, G. Rappl, W. Tilgen, and U. Reinhold Extracellular Tyrosinase mRNA within Apoptotic Bodies Is Protected from Degradation in Human Serum Clin. Chem., August 1, 2001; 47(8): 1488 - 1489. [Full Text] [PDF]
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). B, methylation-specific PCR of
controls: HUVECs, HeLa cells, and HL60 cells. C,
methylation-specific PCR of representative samples: tumor tissue of
patient T2 and plasma samples of cancer patients C11 and
C14. Lanes U and
M, unmethylated and methylated reactions,
respectively.
