Reviewer's report
Title:KRAS mutations: variable incidences in a Brazilian cohort of 8,234
metastatic colorectal cancer patients
Version:1Date:1 February 2014
Reviewer: Grazia Palomba
Reviewer's report:
“KRAS mutations: variable incidences in a Brazilian cohort of 8,234 metastatic
colorectal cancer patients”
The aim of the study is to assess the distribution of KRAS mutations in Brazilian
metastatic colorectal cancer patients.
Major Compulsory Revisions
KRAS point mutations are highly prevalent in CRC and mostly occur in codons
12, 13, and 61. The profile of KRAS mutations was analyzed by direct
sequencing of KRAS codons 12 and 13 only. Although not frequently mutated in
CRC (5-6% of cases), codon 61 should have been analyzed (in this large
patients’ collection, more than 400 cases could have been misclassified).
More information about the distribution of mutations, according to additional
clinico-pathological characteristics of CRC patients, should be presented [mainly,
anatomical site of primary tumor (right, transverse, left colon, etc.), disease
stage, tumor grading].
The discussion about the importance of sexual hormones in the risk for CRC
should be more concise. Previous studies have indeed investigated sex-related
differences in the prognostic impact of KRAS and BRAF mutation in CRC. No
significant association was found between KRAS mutations and sex. Further
studies directly focused on the associations of hormonal factors with KRAS
mutation status in CRC are awaited.
Minor Essential Revisions
Methods: why did the authors use the semi-nested PCR for the mutational
analysis?
Results: In the first paragraph of the Results, the last sentence should be
removed (it has been repeated twice the fact that a part of samples was not
analyzed).
Level of interest: An article of limited interest
Quality of written English: Acceptable
Statistical review: Yes, but I do not feel adequately qualified to assess the
statistics.
Declaration of competing interests:
I declare that I have no competing interests.
Reviewer's report
Title:KRAS mutations: variable incidences in a Brazilian cohort of 8,234
metastatic colorectal cancer patients
Version:1Date:1 February 2014
Reviewer: Grazia Palomba
Reviewer's report:
“KRAS mutations: variable incidences in a Brazilian cohort of 8,234 metastatic
colorectal cancer patients”
The aim of the study is to assess the distribution of KRAS mutations in Brazilian
metastatic colorectal cancer patients.
Major Compulsory Revisions
KRAS point mutations are highly prevalent in CRC and mostly occur in codons
12, 13, and 61. The profile of KRAS mutations was analyzed by direct
sequencing of KRAS codons 12 and 13 only. Although not frequently mutated in
CRC (5-6% of cases), codon 61 should have been analyzed (in this large
patients’ collection, more than 400 cases could have been misclassified).
More information about the distribution of mutations, according to additional
clinico-pathological characteristics of CRC patients, should be presented [mainly,
anatomical site of primary tumor (right, transverse, left colon, etc.), disease
stage, tumor grading].
The discussion about the importance of sexual hormones in the risk for CRC
should be more concise. Previous studies have indeed investigated sex-related
differences in the prognostic impact of KRAS and BRAF mutation in CRC. No
significant association was found between KRAS mutations and sex. Further
studies directly focused on the associations of hormonal factors with KRAS
mutation status in CRC are awaited.
Minor Essential Revisions
Methods: why did the authors use the semi-nested PCR for the mutational
analysis?
Results: In the first paragraph of the Results, the last sentence should be
removed (it has been repeated twice the fact that a part of samples was not
analyzed).
Level of interest: An article of limited interest
Quality of written English: Acceptable
Statistical review: Yes, but I do not feel adequately qualified to assess the
statistics.
Declaration of competing interests:
I declare that I have no competing interests.
Please review this paper.
user
Reviewer's report
Title:KRAS mutations: variable incidences in a Brazilian cohort of 8,234
metastatic colorectal cancer patients
Version:1Date:1 February 2014
Reviewer: Grazia Palomba
Reviewer's report:
“KRAS mutations: variable incidences in a Brazilian cohort of 8,234 metastatic
colorectal cancer patients”
The aim of the study is to assess the distribution of KRAS mutations in Brazilian
metastatic colorectal cancer patients.
Major Compulsory Revisions
KRAS point mutations are highly prevalent in CRC and mostly occur in codons
12, 13, and 61. The profile of KRAS mutations was analyzed by direct
sequencing of KRAS codons 12 and 13 only. Although not frequently mutated in
CRC (5-6% of cases), codon 61 should have been analyzed (in this large
patients’ collection, more than 400 cases could have been misclassified).
More information about the distribution of mutations, according to additional
clinico-pathological characteristics of CRC patients, should be presented [mainly,
anatomical site of primary tumor (right, transverse, left colon, etc.), disease
stage, tumor grading].
The discussion about the importance of sexual hormones in the risk for CRC
should be more concise. Previous studies have indeed investigated sex-related
differences in the prognostic impact of KRAS and BRAF mutation in CRC. No
significant association was found between KRAS mutations and sex. Further
studies directly focused on the associations of hormonal factors with KRAS
mutation status in CRC are awaited.
Minor Essential Revisions
Methods: why did the authors use the semi-nested PCR for the mutational
analysis?
Results: In the first paragraph of the Results, the last sentence should be
removed (it has been repeated twice the fact that a part of samples was not
analyzed).
Level of interest: An article of limited interest
Quality of written English: Acceptable
Statistical review: Yes, but I do not feel adequately qualified to assess the
statistics.
Declaration of competing interests:
I declare that I have no competing interests.
assistant