Establishment of serum protein pattern for screening colorectal cancer using SELDI-TOF-MS
Aim: The purpose of this study is to develop a proteomic pattern for distinguishing individuals with colorectal cancer from healthy controls and monitoring micrometastasis using SELDI-TOF-MS. Methods: A training set consisting of 63 patients with colorectal cancer, 20 patients with benign colorectal...
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Інститут експериментальної патології, онкології і радіобіології ім. Р.Є. Кавецького НАН України
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| Цитувати: | Establishment of serum protein pattern for screening colorectal cancer using SELDI-TOF-MS / G.X. Zheng, C.X. Wang, X. Qu, X.M. Deng, B.P. Deng, J. Zhang // Experimental Oncology. — 2006. — Т. 28, № 4. — С. 282-287. — Бібліогр.: 22 назв. — англ. |
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irk-123456789-1379302018-06-18T03:08:44Z Establishment of serum protein pattern for screening colorectal cancer using SELDI-TOF-MS Zheng, G.X. Wang, C.X. Qu, X. Deng, X.M. Deng, B.P. Zhang, J. Original contributions Aim: The purpose of this study is to develop a proteomic pattern for distinguishing individuals with colorectal cancer from healthy controls and monitoring micrometastasis using SELDI-TOF-MS. Methods: A training set consisting of 63 patients with colorectal cancer, 20 patients with benign colorectal diseases and 26 healthy volunteers was used to develop a proteomic model that discriminated colorectal cancer effectively. The sensitivity and specificity of this model was validated by an independent test set. To explore serum proteins changed after operation, the protein profiles of 31 postoperative patients were compared with those of preoperative patients. We also analyzed protein profiles of patients with and without metastasis to monitor micrometastasis. Results: Our study yielded a four-peak model (m/z: 3191.5, 3262.9, 3396.3 and 5334.4) that discriminated cancer from non-cancer samples with sensitivity of 90.3% and specificity of 95.7%. This model was validated in the test set with sensitivity of 87.5% and specificity of 93.8% which was significantly better than the combination use of CEA, CA199 and CA242 (sensitivity 62.4%) for early detection of colorectal cancer. Two peaks (m/z: 2753.8 and 4172.4) were found down-regulated in postoperative samples comparing with preoperative samples. We also detected two proteins (m/z: 9184.4 and 9340.9) that can discriminate patients with primary colorectal cancer from metastatic colorectal cancer. Conclusions: The four-peak model and two peaks (m/z: 2753.8 and 4172.4) detected in this study have the potential for assistance in diagnostics and therapeutic strategies in colorectal cancer and the two proteins (m/z: 9184.4 and 9340.9) were effective biomarkers for monitoring micrometastasis. Цель: исследование белкового профиля сыворотки крови больных колоректальным раком и здоровых доноров методом SELDI-TOF-MS для диагностики заболевания и мониторинга микрометастазов. Методы: методом SELDI-TOF-MS исследованы сыворотки крови 63 больных колоректальным раком, 20 больных с доброкачественными новообразованиями прямой кишки и 26 — здоровых доноров. Проведено сравнение профилей белков сыворотки крови 31 больного до и после хирургического вмешательства, а также больных с метастазами или без таковых. Результаты: получена 4-пиковая модель (m/z: 3191,5; 3262,9; 3396,3 и 5334,4), позволяющая отличить опухолевые образцы от неопухолевых с чувствительностью 90,3% и специфичностью 95,7%. Такая модель проверена в тест-системе с чувствительностью 87,5% и специфичностью 93,8%, что является лучшим результатом, чем комбинированное применение CEA, CA199 и CA242 (чувствительность 62,4%) для раннего выявления колоректального рака. Выявлено снижение интенсивности двух пиков (m/z: 2753,8 и 4172,4) при сравнении образцов до и после проведения операции, и идентифицированы два белка (m/z: 9184,4 и 9340,9), позволяющие выявлять больных колоректальным раком с метастазами. Выводы: полученная мод 2006 Article Establishment of serum protein pattern for screening colorectal cancer using SELDI-TOF-MS / G.X. Zheng, C.X. Wang, X. Qu, X.M. Deng, B.P. Deng, J. Zhang // Experimental Oncology. — 2006. — Т. 28, № 4. — С. 282-287. — Бібліогр.: 22 назв. — англ. 1812-9269 http://dspace.nbuv.gov.ua/handle/123456789/137930 en Experimental Oncology Інститут експериментальної патології, онкології і радіобіології ім. Р.Є. Кавецького НАН України |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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DSpace DC |
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English |
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Original contributions Original contributions |
| spellingShingle |
Original contributions Original contributions Zheng, G.X. Wang, C.X. Qu, X. Deng, X.M. Deng, B.P. Zhang, J. Establishment of serum protein pattern for screening colorectal cancer using SELDI-TOF-MS Experimental Oncology |
| description |
Aim: The purpose of this study is to develop a proteomic pattern for distinguishing individuals with colorectal cancer from healthy controls and monitoring micrometastasis using SELDI-TOF-MS. Methods: A training set consisting of 63 patients with colorectal cancer, 20 patients with benign colorectal diseases and 26 healthy volunteers was used to develop a proteomic model that discriminated colorectal cancer effectively. The sensitivity and specificity of this model was validated by an independent test set. To explore serum proteins changed after operation, the protein profiles of 31 postoperative patients were compared with those of preoperative patients. We also analyzed protein profiles of patients with and without metastasis to monitor micrometastasis. Results: Our study yielded a four-peak model (m/z: 3191.5, 3262.9, 3396.3 and 5334.4) that discriminated cancer from non-cancer samples with sensitivity of 90.3% and specificity of 95.7%. This model was validated in the test set with sensitivity of 87.5% and specificity of 93.8% which was significantly better than the combination use of CEA, CA199 and CA242 (sensitivity 62.4%) for early detection of colorectal cancer. Two peaks (m/z: 2753.8 and 4172.4) were found down-regulated in postoperative samples comparing with preoperative samples. We also detected two proteins (m/z: 9184.4 and 9340.9) that can discriminate patients with primary colorectal cancer from metastatic colorectal cancer. Conclusions: The four-peak model and two peaks (m/z: 2753.8 and 4172.4) detected in this study have the potential for assistance in diagnostics and therapeutic strategies in colorectal cancer and the two proteins (m/z: 9184.4 and 9340.9) were effective biomarkers for monitoring micrometastasis. |
| format |
Article |
| author |
Zheng, G.X. Wang, C.X. Qu, X. Deng, X.M. Deng, B.P. Zhang, J. |
| author_facet |
Zheng, G.X. Wang, C.X. Qu, X. Deng, X.M. Deng, B.P. Zhang, J. |
| author_sort |
Zheng, G.X. |
| title |
Establishment of serum protein pattern for screening colorectal cancer using SELDI-TOF-MS |
| title_short |
Establishment of serum protein pattern for screening colorectal cancer using SELDI-TOF-MS |
| title_full |
Establishment of serum protein pattern for screening colorectal cancer using SELDI-TOF-MS |
| title_fullStr |
Establishment of serum protein pattern for screening colorectal cancer using SELDI-TOF-MS |
| title_full_unstemmed |
Establishment of serum protein pattern for screening colorectal cancer using SELDI-TOF-MS |
| title_sort |
establishment of serum protein pattern for screening colorectal cancer using seldi-tof-ms |
| publisher |
Інститут експериментальної патології, онкології і радіобіології ім. Р.Є. Кавецького НАН України |
| publishDate |
2006 |
| topic_facet |
Original contributions |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/137930 |
| citation_txt |
Establishment of serum protein pattern for screening colorectal cancer using SELDI-TOF-MS / G.X. Zheng, C.X. Wang, X. Qu, X.M. Deng, B.P. Deng, J. Zhang // Experimental Oncology. — 2006. — Т. 28, № 4. — С. 282-287. — Бібліогр.: 22 назв. — англ. |
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Experimental Oncology |
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| fulltext |
282 Experimental Oncology 28, 282–287, 2006 (December)
Colorectal cancer is the fourth most common ma-
lignancy in the world, accounting for about 10% of all
cancer deaths every year. If patients were diagnosed in
the early stage, the overall five-year survival rate can be
around 90%. However, about in 35% of cases tumors
are not detected until they have invaded the surrounding
tissue or metastasized to distant sites. The relative sur-
vival rate of such patients is less than 40% [1, 2]. Thus,
discovery of specific tumor markers for early diagnosis
is of importance for survival rate and prognosis.
Non-invasive methods for colorectal cancer dia-
gnosis mainly include fecal occult blood testing, fecal
biochemistry and immunology testing, detection of
serum tumor markers and so on [3–5]. All these ap-
proaches are neither sensitive nor specific enough
for use as the sole screening method for early cancer
detection. Novel gene technology, such as microarray
and DNA chip, can identify and quantitative mRNA with
high sensitivity on a global scale [6, 7]. However, it has
been shown that there is no direct correlation between
mRNA and protein expression level in vivo because of
post-transcriptional regulations and post-translational
modifications occured in protein expression and syn-
thesis. The mRNA/protein correlation coefficients are
only 0.4–0.5 and mRNA cannot accurately represent the
quantity of protein which is the true executant of gene
function [8–10]. Therefore, more extensive and effective
tests are desirable for diagnosis of primary cancer.
National Cancer Institute (NCI) gets a conclusion
by clinical experiments: SELDI-TOF-MS is the most
promising technology for early detection of can-
cer [11]. SELDI-TOF mass spectrometry technology is
potentially an important tool for the rapid identification
of cancer specific biomarkers and proteomic pat-
terns in the proteomes of both tissue and body fluids,
especially suitable for serum analysis which contains
abundant low molecular weight and low-abundance
proteins that carry important diagnostic information
but exist below the detection limits of any conventional
testing. An advantage of this technology is its ability
to simultaneously analyze the whole proteome so that
correlated proteins altered in expression can be identi-
fied in a single experiment. This makes it possible to
combine several protein markers together to form a
pattern with higher sensitivity and specificity in the
detection and monitoring of cancer.
The aim of this study was to compare serum
proteomic profiles between patients with colorectal
cancer, benign colorectal disease and healthy cont-
rols to discover colorectal cancer-specific biomarker
proteins, and to validate these biomarkers with an
independent sample set. In addition, protein profiles
of patients with colorectal cancer before and after
operation were also analyzed.
Materials and Methods
Patients and controls. Two independent serum
sample sets were analyzed for their protein profiles.
The training set consisted of samples from 63 patients
establishMent of seruM protein pattern for screening
colorectal cancer using seldi-tof-Ms
G.X. Zheng1, C.X. Wang1, *, X. Qu2, X.M. Deng1, B.P. Deng2, J. Zhang1
1Department of Clinical Laboratory, Qilu Hospital of Shandong University, Ji’nan 250012,
Shandong Province, P.R. China
2Department of Basic Medicine, Qilu Hospital, Shandong University, Ji’nan 250012,
Shandong Province, P.R. China
Aim: The purpose of this study is to develop a proteomic pattern for distinguishing individuals with colorectal cancer from healthy
controls and monitoring micrometastasis using SELDI-TOF-MS. Methods: A training set consisting of 63 patients with colorectal
cancer, 20 patients with benign colorectal diseases and 26 healthy volunteers was used to develop a proteomic model that discrimi-
nated colorectal cancer effectively. The sensitivity and specificity of this model was validated by an independent test set. To explore
serum proteins changed after operation, the protein profiles of 31 postoperative patients were compared with those of preoperative
patients. We also analyzed protein profiles of patients with and without metastasis to monitor micrometastasis. Results: Our study
yielded a four-peak model (m/z: 3191.5, 3262.9, 3396.3 and 5334.4) that discriminated cancer from non-cancer samples with
sensitivity of 90.3% and specificity of 95.7%. This model was validated in the test set with sensitivity of 87.5% and specificity of
93.8% which was significantly better than the combination use of CEA, CA199 and CA242 (sensitivity 62.4%) for early detection
of colorectal cancer. Two peaks (m/z: 2753.8 and 4172.4) were found down-regulated in postoperative samples comparing with
preoperative samples. We also detected two proteins (m/z: 9184.4 and 9340.9) that can discriminate patients with primary colorectal
cancer from metastatic colorectal cancer. Conclusions: The four-peak model and two peaks (m/z: 2753.8 and 4172.4) detected in
this study have the potential for assistance in diagnostics and therapeutic strategies in colorectal cancer and the two proteins (m/z:
9184.4 and 9340.9) were effective biomarkers for monitoring micrometastasis.
Key Words: SELDI-TOF, proteomics, colorectal cancer, biomarker, metastasis.
Exp Oncol 2006
28, 4, 282–287
Received: November 8, 2006.
*Correspondence: E-mail: wcx6601@126.com
Abbreviations used: CA199 – carbohydrate antigen 199; CA242 —
carbohydrate antigen 242; CEA — carcinoembryonic antigen;
SELDI-TOF-MS — surface-enhanced laser desorption/ionization
time-of-flight mass spectrometry.
Experimental Oncology 28, 282–287, 2006 (December) 28328, 282–287, 2006 (December) 283December) 283) 283 283
with colorectal cancer (Dukes’A, n = 14, Dukes’B, n =
19, Dukes’C, n = 17, Dukes’D, n = 13), 20 patients with
benign colorectal diseases and 26 healthy volunteers.
The test set consisted of samples from 48 patients with
colorectal cancer (Dukes’A, n = 10, Dukes’B, n = 15,
Dukes’C, n = 14, Dukes’D, n = 9), 18 patients with
benign colorectal diseases and 14 healthy volunteers.
The mean age of cancer patients was 56.7 ± 7.3 years
(range 49–75 years) while the mean age of control
group was 54.2 ± 3.5 years (range 46–69 years).
There was no statistically significant difference in the
ages between the two groups (P > 0.05). Additional
31 postoperative patients with colorectal cancer were
also analyzed. All the serum samples were examined
in the laboratory to eliminate diseases influenced
content of proteins, such as liver disease. The study
was performed after approval by our institute Human
Investigations Committee and consent of all the pa-
tients and healthy volunteers.
Samples. 5 ml of peripheral blood were collected
from the cancer patients and healthy subjects. All the
samples were collected before operation and any
treatment. For the 31 postoperative patients, blood
samples were collected at the 14th day after opera-
tion. Each sample was placed at 4 °C for 2 h and was
centrifuged at 3000 r/min for 10 min to remove cel-
lular components. Serum samples were collected,
aliquoted and kept frozen at –80 °C until use. CEA,
CA199, CA242 levels were examined previously.
SELDI analysis. Four types of chip (hydropho-
bic chip, strong anion exchanger chip, weak cation
exchanger chip and immobilized metal anion chip)
were tested to determine which could provide the
best serum profiles. After evaluation, the weak cation
exchanger (WCX) Protein Chip which contains anionic
carboxylate groups that bind positively charged pro-
teins in serum was selected for our study.
Serum samples were denatured by adding 20 μl U9
(9 M urea, 2% CHAPS, 50 mM Tris-HCl, pH = 9.0)
to 10 μl serum, then adding 360 μl binding buffer.
Subsequently, 150 μl denatured samples was applied
on Protein Chip which had previously been activated
with 10 mM HCl and equilibrated with binding buffer
(100 mM ammonium acetate) according to the manu-
facturer’s instructions. After the samples were allowed
to incubate for 60 min on a platform shaker, the array
was washed twice with 200 μl binding buffer for 5 min,
followed by two quick rinses with HEPES solution. Be-
fore SELDI analysis, 0.5 μl of a saturated SPA solution
(sinapinic acid in 50% aqueous acetonitrile and 0.5%
trifluoroacetic acid) was applied onto each chip array
twice, allowing the array surface to air-dry between
each SPA application. Chips were placed on the Protein
Biological System II mass spectrometer reader and
time-of-flight spectra were generated by averaging
60 laser shots collected in the positive mode at laser
intensity 165 and detector sensitivity 8. Mass accuracy
was calibrated on the day of measurements using the
All-in-one peptide molecular mass standard.
The reproducibility of SELDI spectra, that is, mass
location and intensity from array to array on a single
chip (intra-assay) and between chips (interassay),
was determined using the pooled normal serum quali-
ty control (QC) sample. We compared the average
intensity of all peaks in the range of 2000–30000 Da
observed on spectra and calculated the coefficient of
variance. The intra-assay analyses were performed
in quadruplicate, and the inter-assay analyses were
performed on three different days.
Statistical analysis. Peak detection was per-
formed using Ciphergen ProteinChip software ver-
sions 3.2. The mass range from 2000 to 30000 Da
was selected. We focused on this region to eliminate
low-mass (m/z < 2000) and low-intensity peaks
(m/z > 30000). Peak detection involved (a) baseline
subtraction, (b) mass accuracy calibration and (c)
automatic peak detection. Using Biomarker Wizard
(BMW) software, biomarkers were generated which
represented consistent protein peak sets across
multiple spectra. Next, Biomarker Patterns software
(BPS) was used to construct the decision tree from the
BMW files. The value of the candidate biomarkers in
detecting colorectal cancer from non-cancer controls
was evaluated by Mann — Whitney U test. Mean spect-
ra generated from preoperative and postoperative
groups, patients with primary colorectal cancer and
metastatic colorectal cancer were compared using
Students t-test.
Serum CEA, CA199 and CA242 quantification.
Serum CEA, CA199 and CA242 were quantified us-
ing an electrochemiluminiscence immunoassay on a
Modular analytics E170 analyser. The cut-off value of
5 ng/mL, 35 KU/L and 20 KU/L were employed for CEA,
CA199 and CA242 respectively. All statistical analyses
for these data were performed with SPSS software.
results
Reproducibility. The reproducibility of SELDI
mass spectra was successfully testified using the quali-
ty control (QC) samples. The intra- and inter-assay
coefficients of variance for peak location were 0.04
and 0.05%, and the intra- and inter-assay coefficients
of variance for normalized intensity (peak height or
relative concentration) were respectively 11 and 14%.
There was little variation with day-to-day sampling and
instrumentation. The acceptable intra- and inter-assay
variations of this method have allowed us to obtain a
reliable result in this study.
Cancer-specific biomarkers detection and se-
lectivity. A total of 127 peaks were identified in the m/z
region of 2000–30 000 from SELDI spectra of training
set. Using Biomarker Wizard software, we compared
the spectra generated from cancer group with corre-
sponding spectra generated from control group. This
comparison yielded 26 differential peaks (Table 1).
Among these, 4 peaks were chose to form a model
that could discriminate colorectal cancer patients from
control group effectively. The 4 peaks corresponded
to m/z ratios of 3191.5, 3262.9, 3396.3 and 5334.4
284 Experimental Oncology 28, 282–287, 2006 (December)
(Table 2, Fig. 1). All the 4 peaks were up-regulated
in the group of patients with colorectal cancer (P <
0.01). The sensitivity and specificity of this model was
respectively 90.3 and 95.7%. A blind test set consisted
of 48 patients with colorectal cancer, 18 patients with
benign colorectal neoplasia and 14 healthy volunteers.
In our study, correctly classification was achieved in 30
of 32 controls and 42 of 48 cancer patients, including
8 of 10 Duke’A patients.
Table 1. Differently expressed proteins in serum of colorectal cancer
group and control group
Mass-charge ratio
of protein (m/z) P value The average intensity of protein peak
Colorectal cancer group Control group
2753.8 0.00004 31.11608654 12.1590982
9289.3 0.00003 24.35909 13.14588
5334.4* 0.00002 22.73111 6.084794
3191.5* 0.0009 7.725975 2.0018
4645.9 0.0009 11.21654 5.426459
3262.9* 0.001 10.033386 3.291793
4172.4 0.001 19.398129 5.92417203
5803.7 0.001 7.97111 1.900566
14123.7 0.001 2.656011 4.71362
14023.8 0.001 4.604952 7.730591
28024.4 0.001 8.792696 15.22274
2963.9 0.002 7.322281 1.991357
5904.1 0.002 42.15694 14.6972
2949.8 0.002 19.81355 5.610585
5831.7 0.002 6.03706 2.348323
3396.3* 0.002 23.88053 8.67945
28858.68 0.002 1.792869 3.191014
13742.1 0.003 2.209401 3.782254
5263.0 0.005 5.592539 1.753355
4671.9 0.007 4.737961 2.475495
5745.4 0.01 2.134776 1.351598
2899.9 0.01 3.988201 0.886663
7971.9 0.01 15.78563 10.27681
15841.9 0.02 13.43144 7.96911
11795.6 0.02 5.15713 1.362526
23369.7 0.04 6.67954 8.803534
The proteomic spectra indicated the average intensity of differently ex-
pressed proteins in two groups. The four peaks that constructed diagnos-
tic model were marked by * sign.
Table 2. Differently expressed proteins in blood serum of preoperative
and postoperative groups
Mass-charge ratio
of protein (m/z) P value The average intensity of protein peak
Preoperative group Postoperative group
2753.8 0.00005 31.21516847 11.2172390
4172.4 0.001 20.0139783 5.78351392
CA199, CA242 and CEA levels were available for
all the cases in training set and test set. We found that
combination of these three markers had the sensitivity
of 62.4% and specificity of 86.2% for distinguishing
colorectal cancer from controls. Obviously, the pro-
teomic model generated from our study had higher
sensitivity than the combination of CA199, CA242
and CEA for diagnosing colorectal cancer (P < 0.005)
though the specificity had no statistic difference.
Different preoperative and postoperative
markers in colorectal cancer. We compared the
preoperative protein profiles with the postoperative
(day 14) profiles for the 31 colorectal cancer patients.
Two peaks (m/z: 2753.8 and 4172.4, Fig. 2) were de-
tected which were down-regulated in 27 of 31 (87.5%)
patients compared to these in preoperative samples.
In an independent test set, the two peaks were also
validated down-regulated in 13 of 16 (81.3%) postope-
rative samples.
fig. 1. (a, b) Proteomic pattern of blood serum samples
of colorectal cancer patients and controls evaluated by
SELDI-TOF-MS. X-axis represents the ratio of mass to charge
of protein, Y-axis represents relative intensity. The profiles
demonstrate up-regulation of m/z 3191.5, 3262.9, 3396.3 and
5334.4 peaks in colorectal cancer patients
Differential markers for primary colorectal
cancer and metastatic colorectal cancer. The
cancer patients of the training set were divided into two
groups (30 patients with metastasis and 33 patients
without metastasis) according to after surgical exami-
nation. Two proteins (m/z: 9184.4 and 9340.9, Fig. 3)
were found that can discriminate the two groups. The
two proteins were observed in all the Duke’A and in 13
of 15 Duke’B patients, absent in 11 of 14 Duke’C and
all Duke’D patients from the test set.
Experimental Oncology 28, 282–287, 2006 (December) 28528, 282–287, 2006 (December) 285December) 285) 285 285
fig. 2. (a, b) Proteomic pattern of blood serum samples of
preoperative patients and postoperative patients evaluated by
SELDI-TOF-MS. X-axis represents the ratio of mass to charge
of protein, Y-axis represents relative intensity. The profiles
demonstrate up-regulation of m/z 2753.8 and 4172.4 peaks in
preoperative patients
discussion
Although diagnostic technology and therapeutic
treatment have made vast progress during the last
decades, the survival rate of patients with colorectal
cancer still has no significant improvement. Without
useful method for early cancer detection is thought
to be responsible for this. Currently, CEA is the best
available marker for colorectal cancer detection. How-
ever, the use of CEA has significant clinical limitation
because of low sensitivity (3–66.7%) [4, 12, 13]. Con-
siderable effort has been taken in identifying potential
markers that might substitute or complement CEA in
screening colorectal cancer.
fig. 3. Proteomic pattern of blood serum samples of colorec-
tal cancer patients with and without metastasis evaluated by
SELDI-TOF-MS. X-axis represents the ratio of mass to charge
of protein, Y-axis represents relative intensity.The profile dem-
onstrates absence of m/z 9184.4 and 9340.9 peaks in patients
with metstatic colorectal cancer
SELDI-TOF-MS is a new type of proteomic platform
which has recently shown tremendous promise in the
detection of various early-stage cancers, such as breast,
ovarian, prostate, gastric cancer and so on [14–17]. It
is especially suitable for examination of small volumes
of samples such as serum which has been proven to
be a rich source of biomarker for the early detection
of cancer [18]. Contrary to genome and other conven-
tional approaches, this method can reflect not only the
presence of active or inactive genes but also their extent
of expression at a specific time point. Furthermore, it
can detect all proteins and peptides that may originate
from the same gene but with different post-translation
modifications. Using SELDI-TOF-MS, novel proteins
specific to certain cancer and characterization of these
proteins can be discovered and captured by compara-
tive analysis of the mass spectra of the samples from
patients and normal controls.
In this study, SELDI-TOF-MS was applied to es-
tablish serum protein pattern for screening colorectal
cancer. We compared protein spectra from patients
who had colorectal cancer with the corresponding
spectra from healthy controls and patients with benign
colorectal disease. Our analysis yielded a proteomic
model consisting of 4 candidate makers (m/z of
3191.5, 3262.9, 3396.3 and 5334.4) which were all
up-regulated in cancer patients. Several reports have
been made of differential expression of the same m/z
values in colorectal cancer, even though different chips
were used. In the study [1] it was reported a 3.3 ×
103 Da protein to be differentially expressed that was
also selected in the final diagnostic pattern. Yu [10,
19] detected a 5.9 × 103 Da protein on a hydrophobic
chip which was an up-regulated biomarker in serum
of colorectal cancer patients. Although we did not se-
286 Experimental Oncology 28, 282–287, 2006 (December)
lect the 5904.6 Da protein to form the final diagnostic
pattern, it was truly differentially expressed in cancer
patients with controls which is consistent with the result
[10, 19]. An effective screening test should achieve a
high sensitivity and specificity. We were encouraged to
find that the proteomic pattern resolved by SELDI may
become a potential diagnostic approach with sensitiv-
ity of 90.3% and specificity of 95.7% in training set and
was validated with high sensitivity and specificity in test
set. This study showed that our proteomic biomarkers
was significantly better than the combination of routine
markers CEA, CA199 and CA242. Eight from ten Duke’A
patients from test set were correctly classified by pro-
teomic model but none by the combination of CEA,
CA199 and CA242. Thus, these proteomic markers
may facilitate early-detection of colorectal cancer.
Finding biomarkers to monitor treatment response
is an issue in tumor research. We analyzed proteomic
changes in the serum of postoperative patients with
colorectal cancer before and after operation. Two
peaks (m/z: 2753.8 and 4172.4) were detected which
were down-regulated in postoperative samples than
preoperative samples. The two proteins were both dif-
ferential biomarkers between colorectal cancer patients
and non-cancer controls and the mean peak intensity
were approximately three times in preoperative patients
than postoperative patients. We hypothesized that these
two biomarker may be oncogene proteins and provide
a new insight into therapeutic strategies and molecular
mechanism behind the process of tumorigenesis.
Colorectal caner metastasis is a complex process
involving multiple changes in gene and protein ex-
pression [20–22]. The success of metastatic cancer
treatment is strongly dependent on early diagnosis
and understanding of the molecule mechanisms and
biological behaviors, especially its infiltration and me-
tastasis. To our knowledge, there is no reports about
serum proteomics of metastatic colorectal cancer by
SELDI-TOF MS before. In this study, the identification of
differential proteins between primary colorectal cancer
and metastatic cancer was also performed. Two peaks
(m/z: 9184.4 and 9340.9) were found that can discrimi-
nate the two groups. The two proteins were observed in
all the Duke’A and 13 of 15 Duke’B patients and absent
in 11 of 14 Duke’C and all Duke’D patients from the test
set. We concluded that these two biomarkers may be
metastasis related proteins and can be used to monitor
micrometastasis at the early stage.
In conclusion, our study has proved that SELDI-
TOF-MS is a very useful and promising tool to detect
new serum tumor biomarkers. These protein markers
will enable a more reliable early diagnosis of colorectal
cancer and facilitate the prediction of their progres-
sion. To confirm our findings in larger number of study
samples and identify the reported biomarker proteins,
a prospective study is recently ongoing.
acknowledgeMents
The authors would like to thank Professor Qingsi He
for assistance in tumor samples collection. This work
was supported by grants from Science and Technolo-
gy Special Foundation from Health Department of
Shandong Province, China.
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Copyright © Experimental Oncology, 2006
скрининг спектра белков сыворотки крови больных
колоректальным раком методом seldi-tof-Msseldi-tof-Ms-tof-Mstof-Ms-MsMs
Цель: исследование белкового профиля сыворотки крови больных колоректальным раком и здоровых доноров методом
SELDI-TOF-MS для диагностики заболевания и мониторинга микрометастазов.-TOF-MS для диагностики заболевания и мониторинга микрометастазов.TOF-MS для диагностики заболевания и мониторинга микрометастазов.-MS для диагностики заболевания и мониторинга микрометастазов.MS для диагностики заболевания и мониторинга микрометастазов. для диагностики заболевания и мониторинга микрометастазов. Методы: методом SELDI-TOF-MSSELDI-TOF-MS-TOF-MSTOF-MS-MSMS
исследованы сыворотки крови 63 больных колоректальным раком, 20 больных с доброкачественными новообразованиями
прямой кишки и 26 — здоровых доноров. Проведено сравнение профилей белков сыворотки крови 31 больного до и после
хирургического вмешательства, а также больных с метастазами или без таковых. Результаты: получена 4-пиковая модель
(m/z: 3191,5�� 3262,9�� 3396,3 и 5334,4), позволя��ая отличить опухолевые образ�ы от неопухолевых с чувствительность�m/z: 3191,5�� 3262,9�� 3396,3 и 5334,4), позволя��ая отличить опухолевые образ�ы от неопухолевых с чувствительность�/z: 3191,5�� 3262,9�� 3396,3 и 5334,4), позволя��ая отличить опухолевые образ�ы от неопухолевых с чувствительность�z: 3191,5�� 3262,9�� 3396,3 и 5334,4), позволя��ая отличить опухолевые образ�ы от неопухолевых с чувствительность�: 3191,5�� 3262,9�� 3396,3 и 5334,4), позволя��ая отличить опухолевые образ�ы от неопухолевых с чувствительность�
90,3% и спе�ифичность� 95,7%. �акая модель проверена в тест-системе с чувствительность� 87,5% и спе�ифичность�и спе�ифичность� 95,7%. �акая модель проверена в тест-системе с чувствительность� 87,5% и спе�ифичность� спе�ифичность� 95,7%. �акая модель проверена в тест-системе с чувствительность� 87,5% и спе�ифичность�спе�ифичность� 95,7%. �акая модель проверена в тест-системе с чувствительность� 87,5% и спе�ифичность� 95,7%. �акая модель проверена в тест-системе с чувствительность� 87,5% и спе�ифичность��акая модель проверена в тест-системе с чувствительность� 87,5% и спе�ифичность�
93,8%, что является лучшим результатом, чем комбинированное применение CEA, CA199 и CA242 (чувствительностьCEA, CA199 и CA242 (чувствительность, CA199 и CA242 (чувствительностьCA199 и CA242 (чувствительность199 и CA242 (чувствительностьCA242 (чувствительность242 (чувствительность
62,4%) для раннего выявления колоректального рака. Выявлено снижение интенсивности двух пиков (m/z: 2753,8 иm/z: 2753,8 и/z: 2753,8 иz: 2753,8 и: 2753,8 и
4172,4) при сравнении образ�ов до и после проведения опера�ии, и идентифи�ированы два белка (m/z: 9184,4 и 9340,9),m/z: 9184,4 и 9340,9),/z: 9184,4 и 9340,9),z: 9184,4 и 9340,9),: 9184,4 и 9340,9),
позволя��ие выявлять больных колоректальным раком с метастазами. Выводы: полученная модель и результаты работы
могут быть полезны для диагностики колоректального рака и мониторинга метастазирования.
Ключевые слова: SELDI-TOF, протеом, колоректальный рак, биомаркер, метастазирование.-TOF, протеом, колоректальный рак, биомаркер, метастазирование.TOF, протеом, колоректальный рак, биомаркер, метастазирование., протеом, колоректальный рак, биомаркер, метастазирование.
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