Reviewer ’s report  
 
Title: Performance of OncoE6 Cervical Test with collection methods enabling self -sampling  
 
Version: 0 Date: 13 Feb 2018  
 
Reviewer: Annarosa Del Mistro  
 
Reviewer's report:  
 
The paper by Krings et al reports the results of a feasibility study on the use of OncoE6 cervical 
test with self -collected lavage samples, in compariso to samples collected by swab and by brush 
(all collected b y a physician). The topic is of interest, as self -sampling can be used to increase 
participation in organized cervical cancer screening of hard -to-reach women. The authors have 
included in the study 20 women with histologically confirmed cervical cancer po sitive for 
HPV16 or HPV18 sequences. The results are good, and indicate that all the sampling methods 
evaluated are technically suitable for the OncoE6 test, but some technical aspects and data need 
to be implemented.  
 
Specific major comments:  
1- M&M, colle ction of samples, line 126: please specify whether the sample collected by a 
polyester tipped swab was dry, and the name of the producer.  
 
2- M&M, OncoE6 test, paragraph 2.2: please specify why the self -sampled lavage and the 
swab -collected sample were enti rely used to perform the test, while only 25% of the brush -
collected specimen (resuspended in ThinPrep) was sufficient; had you previously performed 
pilot analyses to establish the amount of cells necessary for the test? This is an important 
point, and in order to gain more information on the amount of cells collected by the different 
sampling methods, it would be useful to add a new table comparing the DNA concentrations 
of all the samples included in the study.  
 
3- OncoE6 test results, paragraph 3.2 and Ta ble 1: could the HPV16 weak signal observed with 
the sample #14 be due to the positivity for HPV56? Is there any cross -reactivity known for 
the the OncoE6 test?  
 
4- OncoE6 test results, paragraph 3.3: please describe the single nucleotide mutation of the 
sample #5 resulting in an altered E6 protein amino acid sequence in position 6 that was 
responsible for the false negative result.  
 
5- OncoE6 test results, paragraph 3.3, lines 204 -210: I agree that an insufficient cellularity can 
be the cause of the discorda nt results for the sample set #15, but it is not the only explanation 
since other samples with a low DNA concentration (#9 and #18) gave positive results; 
indeed, the representativeness of the collected cells is an important issue and needs additional 
considerations. In this study only women with histologically confirmed cervical cancer 
positive for HPV16 or HPV18 sequences were included; while this allowed testing of the 
different sampling methods in a setting of high sensitivity (and collection of all the  samples 
by a physician prevented variability due to collection by the women) , the principal aim of 
cervical cancer screening is the detection of preneoplastic lesions. It is therefore important to 
understand the factors that may affect the performance of  the test.  
 
6- Table 1: it is not specified to which type of sample the reported DNA concentration is 
referred to; I would suggest to delete this information form this table, and to prepare a new 
table with the DNA concentration of all the samples (see also  comment 2).  
 
Minor comments:  
- Line 74: the hr -HPV types according are 12 (not 14) (Bouvard et al, Lancet Oncol 
2009;10:321 -322) 
 
- Lines 79-82: "(virtually 100% of cervical cancers are caused by HPV)" could be moved to 
line 79 after "hr -HPV"  
 
- Line 85: "ph ysiological" should be substituted by "pathological"  
Are the methods appropriate and well described?  
If not, please specify what is required in your comments to the authors.  
 
No 
 
Does the work include the necessary controls?  
If not, please specify which controls are required in your comments to the autho rs. 
 
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 addi tional statistical review is recommended, please specify what aspects require further  
assessment in your comments to the editors.  
 
Not relevant to this manuscript  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Needs some language corrections before being published  
 
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 wa y 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 from 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 al l 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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