Review for 10.1186/s12876-019-1094-x (2019)

Reviewer’s report  
 
Title: Rapidly declining trend of signet ring cell cancer of the stomach may parallel the 
infection rate of Helicobacter pylori  
 
Version: 0 Date: 25 Jul 2019  
 
Reviewer: Giovanni Mario Pes  
 
Reviewer's report:  
 
Study summary  
 
The manuscript by Ohyama and co -authors describes an investigation into the temporal 
changes in the incidence of two types of gastric cancer, signet ring carcinoma and non‒signet 
ring carcinoma, using cancer registry dataof the hospital population of Kōfu City, Japan, over 
a period of ten years. Variation of cancer incidence was compared with changing trends in the 
prevalence of H. pylori infection.  
 
On the basis of their findings, the authors state that there is a parallel decline in the 
prevalence of H. p ylori infection and decreased incidence of signet ring cancer in the last 
twenty years.  
 
The manuscript is very well written. The sample size is adequate, statistical analysis is 
excellent, and the conclusions are supported by the findings.  
 
Comments for the authors  
 
At page 6, lines 9‒12 the authors inaccurately reported the temporal change of the prevalence 
of H. pylori infection in Japan by referring to Inoue's article (ref. 12). That article mentioned 
a previous publication according to which the preva lence was 80% in subjects born before 
1950 and about 5% in those born after 1980, that is, underlined the existence of an authentic 
birth cohort effect. In the present manuscript the authors seem to give the impression that the 
difference was between the t wo epochs (period) rather than between generations (birth 
cohort).  
 
In their analysis, as shown in figure 1b and 1c, the authors used as significant jointpoints 
those of 1949 and 1961. These two values actually derive from the regression analysis of the 
Watanabe's study (ref. 13) on another dataset, and corresponded to the times in which the 
change of trend was statistically significant. On what basis do the authors believe that these 
points are also valid for the dataset used in the present study?  
 
At page  10, lines 40‒60, the authors describe a molecular method (based on 16S rRNA 
amplification) to detect H. pylori in paraffin tissues of patients with signet cell carcinoma. 
The oligoprimers reported are those described by Ho in 1991. However in 1999 Lu et a l. 
compared five molecular methods for detection of H. pylori in gastric tissues, including the 
16S rRNA method (Lu et al, J Clin Microbiol 1999; 37: 772 -774) and found that, 
unfortunately, this PCR has a very poor specificity, namely, it nonspecifically amplifies 
human DNA, not only that of H. pylori. Could this have overestimated the frequency of H. 
pylori infection in the recorded series of signet ring carcinomas?  
Minor comments:  
 
Page 5, lines 26‒27:  I think that the acronym is misplaced. The authors  should choose 
between "Signe ring cell (SRC) carcinoma" and "Signet ring cell carcinoma (SRCC)"  
 
Page 6, line 19. Better "a rapid decline in the prevalence".  
 
Page 10, line 46. Better "magnetic beads".  
 
Page 27, reference 17  The name of the Journal is not "A m J Pathol" but "Am J Surg Pathol".  
 
Page 28, reference 25  The name of the last author is missing "Alfred I Neugut".  
 
Page 30, reference 40  The name of the fifth author is Paolo Bechi, therefore he should be 
reported as "Bechi P"  
 
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
Yes 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the authors.  
 
Yes 
 
Are the conclusions drawn adequately supported by the data shown?  
If not, please explain in your comments to the authors.  
 
Yes 
 
Are you able to assess any statistics in the manuscript or would you recommend an 
additional statistical review?  
If an additional statistical review is recommended, please specify what aspects require further 
assessment in your comments to the editors.  
 
I am able to assess the statistics  
 
Quality of written English  
Please indicate the quality of language in the manus cript:  
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from 
an organisation that may in any way gain or lose financially from the publication of 
this manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose 
financially fro m the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents relating to the content of 
the manuscript?  
 
4. Have you received reimbursements, fees, funding, or salary from an organization that 
holds or has applied for patents relating to the content of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have no competing interests' 
below.  
If your reply is yes to any, please give details below.  
 
I declare that I have no competing interests  
 
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