Reviewer's report
Title:Over-expression of COX-2 mRNA in colorectal cancer
Version: 1Date:25 August 2013
Reviewer: Wenjuan He
Reviewer's report:
Hennie MJ Roelofs et al. conducted mRNA analysis of COX2 expression in 60
patients comparing colorectal cancer tissues with nearby normal tissues using
three different normalization methods, tissue weight or house-keeping genes
B2M or GAPDH. Their data demonstrated statistically significant over-expression
of COX2 mRNA in tumor tissues by all of the three normalization methods.
Normalization by tissue weight has shown the best correlation, with increased
COX2 in around 80% of all patient tumor samples. The authors hence concluded
that examination of COX2 mRNA and normalization by tissue weight is the best
method for determining COX2 levels in colorectal cancer and their data is
consistent with COX2 as a risk biomarker for this type of cancer.
In summary, the present study is carefully designed, well described and it is a
relatively large scale analysis compared to similar published studies examining
COX2 expression in colorectal cancer. My concerns or comments are listed
below which should be addressed to improve the present manuscript.
Major Compulsory Revisions
1. The authors found COX2 mRNA expression normalized by tissue weight
showed the best correlation with tumor when compared to normalization by other
house-keeping genes. Was this due to the fact that some house-keeping gene
expression also changed in tumor tissues?
2. Can absolute quantification method be used to measure COX2 mRNA level
instead of relying on normalization?
3. Did COX1 mRNA expression change in tumor tissues? COX1 is a very good
control to compare to COX2.
4. Western blot or immunostaining to confirm up-regulation of COX2 protein
expression is important supporting data to show.
5. The authors found COX2 expression level was independent of tumor grade or
lymph node metastases. Could the authors further comment on the role of COX2
during colorectal cancer development? And whether patients with up-regulated
COX2 expression or not respond differently to COX2 inhibitor treatment?
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.
Declaration of competing interests:
I declare that I have no competing interests.
Reviewer's report
Title:Over-expression of COX-2 mRNA in colorectal cancer
Version: 1Date:25 August 2013
Reviewer: Wenjuan He
Reviewer's report:
Hennie MJ Roelofs et al. conducted mRNA analysis of COX2 expression in 60
patients comparing colorectal cancer tissues with nearby normal tissues using
three different normalization methods, tissue weight or house-keeping genes
B2M or GAPDH. Their data demonstrated statistically significant over-expression
of COX2 mRNA in tumor tissues by all of the three normalization methods.
Normalization by tissue weight has shown the best correlation, with increased
COX2 in around 80% of all patient tumor samples. The authors hence concluded
that examination of COX2 mRNA and normalization by tissue weight is the best
method for determining COX2 levels in colorectal cancer and their data is
consistent with COX2 as a risk biomarker for this type of cancer.
In summary, the present study is carefully designed, well described and it is a
relatively large scale analysis compared to similar published studies examining
COX2 expression in colorectal cancer. My concerns or comments are listed
below which should be addressed to improve the present manuscript.
Major Compulsory Revisions
1. The authors found COX2 mRNA expression normalized by tissue weight
showed the best correlation with tumor when compared to normalization by other
house-keeping genes. Was this due to the fact that some house-keeping gene
expression also changed in tumor tissues?
2. Can absolute quantification method be used to measure COX2 mRNA level
instead of relying on normalization?
3. Did COX1 mRNA expression change in tumor tissues? COX1 is a very good
control to compare to COX2.
4. Western blot or immunostaining to confirm up-regulation of COX2 protein
expression is important supporting data to show.
5. The authors found COX2 expression level was independent of tumor grade or
lymph node metastases. Could the authors further comment on the role of COX2
during colorectal cancer development? And whether patients with up-regulated
COX2 expression or not respond differently to COX2 inhibitor treatment?
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.
Declaration of competing interests:
I declare that I have no competing interests.
Please review this paper.
user
Reviewer's report
Title:Over-expression of COX-2 mRNA in colorectal cancer
Version: 1Date:25 August 2013
Reviewer: Wenjuan He
Reviewer's report:
Hennie MJ Roelofs et al. conducted mRNA analysis of COX2 expression in 60
patients comparing colorectal cancer tissues with nearby normal tissues using
three different normalization methods, tissue weight or house-keeping genes
B2M or GAPDH. Their data demonstrated statistically significant over-expression
of COX2 mRNA in tumor tissues by all of the three normalization methods.
Normalization by tissue weight has shown the best correlation, with increased
COX2 in around 80% of all patient tumor samples. The authors hence concluded
that examination of COX2 mRNA and normalization by tissue weight is the best
method for determining COX2 levels in colorectal cancer and their data is
consistent with COX2 as a risk biomarker for this type of cancer.
In summary, the present study is carefully designed, well described and it is a
relatively large scale analysis compared to similar published studies examining
COX2 expression in colorectal cancer. My concerns or comments are listed
below which should be addressed to improve the present manuscript.
Major Compulsory Revisions
1. The authors found COX2 mRNA expression normalized by tissue weight
showed the best correlation with tumor when compared to normalization by other
house-keeping genes. Was this due to the fact that some house-keeping gene
expression also changed in tumor tissues?
2. Can absolute quantification method be used to measure COX2 mRNA level
instead of relying on normalization?
3. Did COX1 mRNA expression change in tumor tissues? COX1 is a very good
control to compare to COX2.
4. Western blot or immunostaining to confirm up-regulation of COX2 protein
expression is important supporting data to show.
5. The authors found COX2 expression level was independent of tumor grade or
lymph node metastases. Could the authors further comment on the role of COX2
during colorectal cancer development? And whether patients with up-regulated
COX2 expression or not respond differently to COX2 inhibitor treatment?
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.
Declaration of competing interests:
I declare that I have no competing interests.
assistant