Reviewer's report
Title:Serum trefoil factor 3 as a promising non-invasive biomarker for gastric
cancer screening: A monocentric cohort study in China
Version:10Date:22 December 2013
Reviewer: Katsunori Iijima
Reviewer's report:
The authors demonstrated the usefulness of serum TFF3 as a promising
biomarker for gastric cancer comparing that of serum pepsinogen, and concluded
that serum TFF3 measurement is a better biomarker of gastric cancer than
serum PG measurement. I admit it is a clinically important issue, but I found the
following concerns.
There have already a few studies to investigate the usefulness of serum TFF3 for
detection for gastric cancer (ref.25, 33). Compared with these previous studies,
the present study comprised much smaller cases with gastric cancer (n=183 or
192 in previous studies vs. n=72 in the present study). Inclusion of a small
number of gastric cancer patients is a major limitation of this study.
I also found that there is a serious problem for the definition of gastric atrophy
with serum PG in the present study. The authors used European assay kit
(GastroPanel) for pepsinogen measurement, but they applied the Japanese
criteria for definition of gastric atrophy (PG I <70 ng/mL and PG I/II ratio < 3.0).
However, two recent paper (Iijima K, et al. Serum biomarker tests in delineation
between patients with gastric atrophy or healthy, normal stomach. World J
Gastroenterol. 2009; 21;15:853-9. & Miki K, et al. Cautious comparison between
East and West is necessary in terms of the serum pepsinogen test. Dig Endosc.
2009;21:134-5) reported that serum PG I values in GastroPanel examination
gave exactly twice as high PG I levels as the Japanese assays, while no
differences occurred between the PG II tests. Correspondingly, the PG I/II ratio in
the GastroPanel examination was exactly twice as high as the ratio in the
Japanese tests. Therefore, the definition of gastric atrophy in the present study
was too strict because it corresponded to PG I <35, PG I/II<1.5 in employing
Japanese assay kit. I think that the maneuver well explained the too low
sensitivity (37.5%) of PG test in this study compared with previous studies using
Japanese assay kit (sensitivity 45%-77%). At the same time, specificity of the PG
test of the present study (81.1%) is relatively high compared with previous study
(68%-87%). I think the Japanese criteria of serum PG should not be applied for
the results obtained with European assay kit. I would like authors to recalculate
their results with proper definition or to discuss this issue as a limitation.
The authors enrolled 61 patients with CAG and 27 patients with CNAG. I would
like to know the details as to how the authors define CAG or CNAG. Are they
histologically defined? Where are biopsies taken? How many biopsies? What
kind of grading scale for the histological assessment?
Level of interest: An article of limited interest
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a statistician.
Reviewer's report
Title:Serum trefoil factor 3 as a promising non-invasive biomarker for gastric
cancer screening: A monocentric cohort study in China
Version:10Date:22 December 2013
Reviewer: Katsunori Iijima
Reviewer's report:
The authors demonstrated the usefulness of serum TFF3 as a promising
biomarker for gastric cancer comparing that of serum pepsinogen, and concluded
that serum TFF3 measurement is a better biomarker of gastric cancer than
serum PG measurement. I admit it is a clinically important issue, but I found the
following concerns.
There have already a few studies to investigate the usefulness of serum TFF3 for
detection for gastric cancer (ref.25, 33). Compared with these previous studies,
the present study comprised much smaller cases with gastric cancer (n=183 or
192 in previous studies vs. n=72 in the present study). Inclusion of a small
number of gastric cancer patients is a major limitation of this study.
I also found that there is a serious problem for the definition of gastric atrophy
with serum PG in the present study. The authors used European assay kit
(GastroPanel) for pepsinogen measurement, but they applied the Japanese
criteria for definition of gastric atrophy (PG I <70 ng/mL and PG I/II ratio < 3.0).
However, two recent paper (Iijima K, et al. Serum biomarker tests in delineation
between patients with gastric atrophy or healthy, normal stomach. World J
Gastroenterol. 2009; 21;15:853-9. & Miki K, et al. Cautious comparison between
East and West is necessary in terms of the serum pepsinogen test. Dig Endosc.
2009;21:134-5) reported that serum PG I values in GastroPanel examination
gave exactly twice as high PG I levels as the Japanese assays, while no
differences occurred between the PG II tests. Correspondingly, the PG I/II ratio in
the GastroPanel examination was exactly twice as high as the ratio in the
Japanese tests. Therefore, the definition of gastric atrophy in the present study
was too strict because it corresponded to PG I <35, PG I/II<1.5 in employing
Japanese assay kit. I think that the maneuver well explained the too low
sensitivity (37.5%) of PG test in this study compared with previous studies using
Japanese assay kit (sensitivity 45%-77%). At the same time, specificity of the PG
test of the present study (81.1%) is relatively high compared with previous study
(68%-87%). I think the Japanese criteria of serum PG should not be applied for
the results obtained with European assay kit. I would like authors to recalculate
their results with proper definition or to discuss this issue as a limitation.
The authors enrolled 61 patients with CAG and 27 patients with CNAG. I would
like to know the details as to how the authors define CAG or CNAG. Are they
histologically defined? Where are biopsies taken? How many biopsies? What
kind of grading scale for the histological assessment?
Level of interest: An article of limited interest
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a statistician.
Please review this paper.
user
Reviewer's report
Title:Serum trefoil factor 3 as a promising non-invasive biomarker for gastric
cancer screening: A monocentric cohort study in China
Version:10Date:22 December 2013
Reviewer: Katsunori Iijima
Reviewer's report:
The authors demonstrated the usefulness of serum TFF3 as a promising
biomarker for gastric cancer comparing that of serum pepsinogen, and concluded
that serum TFF3 measurement is a better biomarker of gastric cancer than
serum PG measurement. I admit it is a clinically important issue, but I found the
following concerns.
There have already a few studies to investigate the usefulness of serum TFF3 for
detection for gastric cancer (ref.25, 33). Compared with these previous studies,
the present study comprised much smaller cases with gastric cancer (n=183 or
192 in previous studies vs. n=72 in the present study). Inclusion of a small
number of gastric cancer patients is a major limitation of this study.
I also found that there is a serious problem for the definition of gastric atrophy
with serum PG in the present study. The authors used European assay kit
(GastroPanel) for pepsinogen measurement, but they applied the Japanese
criteria for definition of gastric atrophy (PG I <70 ng/mL and PG I/II ratio < 3.0).
However, two recent paper (Iijima K, et al. Serum biomarker tests in delineation
between patients with gastric atrophy or healthy, normal stomach. World J
Gastroenterol. 2009; 21;15:853-9. & Miki K, et al. Cautious comparison between
East and West is necessary in terms of the serum pepsinogen test. Dig Endosc.
2009;21:134-5) reported that serum PG I values in GastroPanel examination
gave exactly twice as high PG I levels as the Japanese assays, while no
differences occurred between the PG II tests. Correspondingly, the PG I/II ratio in
the GastroPanel examination was exactly twice as high as the ratio in the
Japanese tests. Therefore, the definition of gastric atrophy in the present study
was too strict because it corresponded to PG I <35, PG I/II<1.5 in employing
Japanese assay kit. I think that the maneuver well explained the too low
sensitivity (37.5%) of PG test in this study compared with previous studies using
Japanese assay kit (sensitivity 45%-77%). At the same time, specificity of the PG
test of the present study (81.1%) is relatively high compared with previous study
(68%-87%). I think the Japanese criteria of serum PG should not be applied for
the results obtained with European assay kit. I would like authors to recalculate
their results with proper definition or to discuss this issue as a limitation.
The authors enrolled 61 patients with CAG and 27 patients with CNAG. I would
like to know the details as to how the authors define CAG or CNAG. Are they
histologically defined? Where are biopsies taken? How many biopsies? What
kind of grading scale for the histological assessment?
Level of interest: An article of limited interest
Quality of written English: Acceptable
Statistical review: No, the manuscript does not need to be seen by a statistician.
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