Plasma Bacterial DNA Load as a Potential Biomarker for the Early Detection of Colorectal Cancer: A Case–Control Study

Round 1

Reviewer 1 Report

The manuscript "Role of plasma bacterial DNA in CRC patients: a case-control study" fits well for this journal and will be interesting for both microbiologists and oncologists. The average evaluation of this manuscript is very positive. However, I strongly recommend to correct and clarify some points.

1) The title of the manuscript is too common. The authors tried to study diagnostical or prognostic role of bacterial DNA load in CRC patients. So, title should be corrected in this aspect.

2) Lines 92 and 93. Please, indicate the primers as Forward and Reverse, whereas 50- and -30 should be changed into 5'- and -3'.

3) Line 305. "Escherichia, Shigella" should be written as Escherichia-Shigella or Escherichia / Shigella, because in the data of DNA metabarcoding used for gut microbiome studies, these genera are not able to be differentiated.

4) Along the manuscript all Latin names of bacteria should be written with Italic font, like this: Escherichia-Shigella.

5) Inverse correlation between tumor mass and bacterial DNA load found by the authors deserves at least a short discussion, using comparison with available literature, and attempts of the authors to explain this phenomenon.

6) The groups for comparison are not equal. In CRC group the percentage of patients with hypertension, diabetes, comorbidities was significantly higher than in control group. CRC patients had statistically more significant age, BMI, male proportion. This circumstance is a limitation, which weakens conclusions of the authors and should be explained.

Author Response

Comments have been attached.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript concerns a highly important, actually interesting issue - the connection between human microbiota and health/disease.

 

Some sugesstions:

-Authors should carefully revise the article - in the text are many typos.

-The Headings in the Abstract are unnecessary. Please, remove.

-Fusobacterium nucleatum and other names of bacteria should be written in italics.

-Line 63: from Mar: May or March, please update.

-Please, divide 2.1 Heading into two separate: Population and Blood sample collection.

-Please, add exclusion criteria of the examined group in the Method (Population) section.

-Did the authors examine the distribution of the variables? Add the information to Statistical Analysis. Same as information about p-value which was considered as a statistically significant 

-The authors found differences in many factors between examined groups. Why the correlations with bacterial DNA (f.e. Spearman rank) were not performed?

-In the Discussion section, the authors compare their results very little with those of other authors. The literature on this topic should be discussed more extensively, f.e

Xiao, Q., Lu, W., Kong, X., Shao, Y. W., Hu, Y., Wang, A., ... & Ding, K. (2021). Alterations of circulating bacterial DNA in colorectal cancer and adenoma: A proof-of-concept study. Cancer letters, 499, 201-208.

Speciani, M. C., Cintolo, M., Marino, M., Oren, M., Fiori, F., Gargari, G., ... & Rossi, M. (2022). Flavonoid intake in relation to colorectal cancer risk and blood bacterial DNA. Nutrients, 14(21), 4516.

Cao, Y., Zheng, X., Hu, Y., Li, J., Huang, B., Zhao, N., ... & Tian, S. (2023). Levels of systemic inflammation response index are correlated with tumor-associated bacteria in colorectal cancer. Cell Death & Disease, 14(1), 69.

-Please, add in conclusion, further direction of studies in examined in the paper field.

Author Response

Comments have been attached.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The corrections performed by the authors made the manuscript acceptable.

 

 

 

 

Reviewer 2 Report

Many thanks for Authors for accurate and in-depth analysis of the suggestions. the manuscript looks great now and I highly recommend the publication.