Review for 10.1186/1471-230X-8-56 (2008)

Reviewer's report
Title:Loss of PTEN expression is associated with colorectal cancer liver
metastasis and poor patient survival
Version: 1Date:10 June 2008
Reviewer: Najah Nassif
Reviewer's report:
This original manuscript makes a significant contribution in the area of PTEN
involvement in colorectal cancer by demonstrating an association between PTEN
expression, colorectal cancer aggressive capacity and patient prognosis and
survival in colorectal cancer patients with liver metastases. This is an important
publication as it is the first report to show an association between tumour PTEN
expression status and poor prognosis in colorectal cancer patients with liver
metastases. Furthermore, the results of this study suggest a potential value in
the diagnostic evaluation of PTEN expression in providing valuable prognostic
information to aid treatment strategies for colorectal cancer patients. The work
presented therefore has some interesting therapeutic implications.
Overall the manuscript is straightforward and clearly written. There are some
minor issues with the manuscript and these are outlined in the revisions sections
below.
Methods
The methods described for this analysis are appropriate and sufficiently rigorous.
The tumours analysed appear well matched with respect to stage, grade and
tumour site and the statistical analyses conducted are appropriate for this study.
Results
Among the colorectal patients with liver metastases (n=69), the authors
demonstrate a significant difference in 5-year survival rate between those
patients with positive PTEN expression and those with negative PTEN
expression with a significantly higher in patients with positive PTEN expression.
This is an interesting result showing an influence of PTEN expression on patient
survival.
Discretionary Revisions
If possible, it may be of interest if the authors could make any comments on the
location of the PTEN staining in terms of cytoplasmic and nuclear staining of
PTEN where PTEN staining is present.
Minor Essential Revisions
(1) Page 1: The running should title should read ‘PTEN in metastatic colorectal
tumors’ and not ‘PTEN in metastatic liver tumors’.
(2) In the materials and methods section, under the heading of
Immunohistochemical evaluation, the authors provide a clear definition of the
criteria used to determine strong (S) staining but do not indicate the criteria for
weak (W) staining. It would be of interest to include these criteria as well.
(3) Page 9, Line 3 of paragraph 1: PI3K should be PIP3 (i.e.
phosphoinositol-3,4,5-triphosphate). The authors are referring to the second
messenger molecule in that sentence and not to the enzyme.
(4) Page 9, paragraph 2, line 4: Instead of the word activation, I suspect the
authors mean antagonism. This would be the appropriate word in this instance.
(5) Page 13, List of Abbreviations: The authors should consider including PIP3
(phosphoinositol-3,4,5-triphosphate) in this list.
(6) Page 19, line 3 of the notes to Table 1: a semicolon is missing after the words
metachronous metastasis.
(7) Page 19, line 7 of the notes to Table 1: N.S., should be not significant. The
letter t is missing from the word not.
(8) Page 20, line 7 of the notes to Table 2: N.S., should be not significant. The
letter t is missing from the word not.
Major Compulsory Revisions
There are no major compulsory revisions required for this manuscript.
Level of interest: An article of importance in its field
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.