Review for 10.1186/1471-230X-13-173 (2013)

Reviewer's report
Title:Correlation between the methylation of SULF2 and WRN promoter and the
irinotecan chemosensitivity in gastric cancer
Version: 3Date:30 May 2013
Reviewer: Mathewos Tessema
Reviewer's report:
The manuscript by Wang et al. is poorly written to a degree that makes it hard to
appreciate the interesting and potentially clinically relevant findings it describes.
In addition to the multiple spelling and punctuation errors that need to be fixed,
the manuscript has some factual errors and confusing descriptions listed below.
Major Compulsory Revisions
1. Table 1. SULF2 is methylated in 29 and unmethylated in 73 of 102 cases.
Thus, tumor grades I, II, III in total cannot be methylated in 39 and unmethylated
in 64 tumors.
2. Although results from reference #3 (referenced wrong, Agrelo R not Ruben A)
justified evaluation of WRN methylation, the results in this study did not show
significant association between WRN methylation and sensitivity to irinotecan.
The authors need to discuss the potential reasons for these differences between
the two studies regarding WRN methylation and irinotecan sensitivity.
Furthermore, combining SULF2 and WRN methylation for predicting irinotecan
sensitivity reduced its significance suggesting SULF2 methylation alone is a
better predictor for irinotecan sensitivity in gastric cancer compared to the
combination of the two genes. The authors need to discuss this as well.
3. Neither the table nor the figures are cited in the manuscript.
4. Result section 2, page 6 paragraph 1. Inhibition rates for the sensitive group
was described as 70.61% but for the resistant group it was described as 0.33
(ratio?). Be consistent in using % or ratio for all. It is also not clear whether this is
the mean or median of the inhibition rates for the group. Describe results for
SULF2 and WRN in separate sentences and cite the figure (s) demonstrating
these results.
5. Result section 3, page 6 paragraph 2. This section is similar to section 2 (even
the titles are the basically the same) and could be described with the previous
section.
6. The authors indicated (page 9, last sentence) that they could compare ISG15
expression with irinotecan sensitivity. That would be a simple but potentially
important experiment and could significantly improve this manuscript.
7. Materials and Methods. What was the reason for selecting the dose and
duration of irinotecan treatment? Was the media changed during the 7 days
period? If so, what happen to the drug treatment?
Minor Essential Revisions
1. Neither the table nor the figures are cited in the manuscript.
2. The following examples are used to demonstrate some of the spelling and
punctuation errors.
a. Spelling errors. Background first sentence, usuassly?
b. Punctuations. Commas and full stops were placed in front of a word or
somewhere in the middle. Page2 lines 2, 17, 19.
3. Page 3, last sentence. Use either bisulfite (most commonly used) or
bisulphate, not both.
4. Page 4, line 5. MSP using genomic DNA is confusing. Genomic DNA is often
refers to the unmodified natural DNA. Replace genomic with modified.
5. Use last names for citing papers. E.g. page 8, line 17 Tessema not Mathewos
et al., page 9, line 4, Agrelo not Ruben.
Level of interest: An article of importance in its field
Quality of written English: Not suitable for publication unless extensively edited
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 interest.