Reviewer's report
Title:Occurence of Helicobacter pylori and Epstein-Barr virus infection in
endoscopic and gastric cancer patients from North Brazil
Version:2Date:10 March 2014
Reviewer: M. Constanza Camargo
Reviewer's report:
The authors examined the associations of gastritis and gastric cancer with
presence of both Helicobacter pylori and Epstein–Barr virus (EBV) among
Brazilian children and adults, respectively. This cross-sectional study was
motivated by the potential influence of EBV infection in gastric carcinogenesis.
The authors concluded that H. pylori infection, but not EBV, is associated with
the diagnosis of severe gastritis and gastric cancer.
Major comments:
• The primary limitation of the gastric cancer analysis is that the contribution of H.
pylori infection might be underestimated by rapid urease testing due to prior H.
pylori eradication treatment or the spontaneous disappearance of the bacterium
from the gastric mucosa during the progression of atrophy to cancer. Additionally,
a basic assumption when evaluating the role of EBV in gastric carcinogenesis is
that the viral infection is a co-factor of a process driven by H. pylori. Therefore,
the comparison of EBV prevalence by H. pylori status is uninformative.
• Regarding non-neoplastic lesions, the description of EBV detection by ISH was
not detailed enough. In particular, please describe selection, magnification and
number of microscopic fields evaluated, and definition of a positive result
(perhaps including a picture).
• The Methods state that PCR for cagA gene was conducted in “…all patients
with HP….” (page 6). However, Tables 1 and 2 present features of
cagA-negative and –positive subjects regardless of H. pylori status. Please
reconcile.
• Describe source populations and selection criteria of study participants (e.g.,
consecutive or random selection, period of collection, etc.)
• Endoscopic examination protocol was not detailed enough and the cited
reference (entitled, “The Sydney System: histological division”) is not applicable.
Please describe endoscopic findings, sites and number of biopsies, etc.
• Authors should acknowledge low statistical power for some comparisons.
Level of interest: An article of limited interest
Quality of written English: Needs some language corrections before being
published
Statistical review: No, the manuscript does not need to be seen by a statistician.
Declaration of competing interests:
I declare that I have no competing interests.
Reviewer's report
Title:Occurence of Helicobacter pylori and Epstein-Barr virus infection in
endoscopic and gastric cancer patients from North Brazil
Version:2Date:10 March 2014
Reviewer: M. Constanza Camargo
Reviewer's report:
The authors examined the associations of gastritis and gastric cancer with
presence of both Helicobacter pylori and Epstein–Barr virus (EBV) among
Brazilian children and adults, respectively. This cross-sectional study was
motivated by the potential influence of EBV infection in gastric carcinogenesis.
The authors concluded that H. pylori infection, but not EBV, is associated with
the diagnosis of severe gastritis and gastric cancer.
Major comments:
• The primary limitation of the gastric cancer analysis is that the contribution of H.
pylori infection might be underestimated by rapid urease testing due to prior H.
pylori eradication treatment or the spontaneous disappearance of the bacterium
from the gastric mucosa during the progression of atrophy to cancer. Additionally,
a basic assumption when evaluating the role of EBV in gastric carcinogenesis is
that the viral infection is a co-factor of a process driven by H. pylori. Therefore,
the comparison of EBV prevalence by H. pylori status is uninformative.
• Regarding non-neoplastic lesions, the description of EBV detection by ISH was
not detailed enough. In particular, please describe selection, magnification and
number of microscopic fields evaluated, and definition of a positive result
(perhaps including a picture).
• The Methods state that PCR for cagA gene was conducted in “…all patients
with HP….” (page 6). However, Tables 1 and 2 present features of
cagA-negative and –positive subjects regardless of H. pylori status. Please
reconcile.
• Describe source populations and selection criteria of study participants (e.g.,
consecutive or random selection, period of collection, etc.)
• Endoscopic examination protocol was not detailed enough and the cited
reference (entitled, “The Sydney System: histological division”) is not applicable.
Please describe endoscopic findings, sites and number of biopsies, etc.
• Authors should acknowledge low statistical power for some comparisons.
Level of interest: An article of limited interest
Quality of written English: Needs some language corrections before being
published
Statistical review: No, the manuscript does not need to be seen by a statistician.
Declaration of competing interests:
I declare that I have no competing interests.
Please review this paper.
user
Reviewer's report
Title:Occurence of Helicobacter pylori and Epstein-Barr virus infection in
endoscopic and gastric cancer patients from North Brazil
Version:2Date:10 March 2014
Reviewer: M. Constanza Camargo
Reviewer's report:
The authors examined the associations of gastritis and gastric cancer with
presence of both Helicobacter pylori and Epstein–Barr virus (EBV) among
Brazilian children and adults, respectively. This cross-sectional study was
motivated by the potential influence of EBV infection in gastric carcinogenesis.
The authors concluded that H. pylori infection, but not EBV, is associated with
the diagnosis of severe gastritis and gastric cancer.
Major comments:
• The primary limitation of the gastric cancer analysis is that the contribution of H.
pylori infection might be underestimated by rapid urease testing due to prior H.
pylori eradication treatment or the spontaneous disappearance of the bacterium
from the gastric mucosa during the progression of atrophy to cancer. Additionally,
a basic assumption when evaluating the role of EBV in gastric carcinogenesis is
that the viral infection is a co-factor of a process driven by H. pylori. Therefore,
the comparison of EBV prevalence by H. pylori status is uninformative.
• Regarding non-neoplastic lesions, the description of EBV detection by ISH was
not detailed enough. In particular, please describe selection, magnification and
number of microscopic fields evaluated, and definition of a positive result
(perhaps including a picture).
• The Methods state that PCR for cagA gene was conducted in “…all patients
with HP….” (page 6). However, Tables 1 and 2 present features of
cagA-negative and –positive subjects regardless of H. pylori status. Please
reconcile.
• Describe source populations and selection criteria of study participants (e.g.,
consecutive or random selection, period of collection, etc.)
• Endoscopic examination protocol was not detailed enough and the cited
reference (entitled, “The Sydney System: histological division”) is not applicable.
Please describe endoscopic findings, sites and number of biopsies, etc.
• Authors should acknowledge low statistical power for some comparisons.
Level of interest: An article of limited interest
Quality of written English: Needs some language corrections before being
published
Statistical review: No, the manuscript does not need to be seen by a statistician.
Declaration of competing interests:
I declare that I have no competing interests.
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