The Role of Biomarkers in the Early Diagnosis of Gastric Cancer: A Study on CCR5, CCL5, PDGF, and EphA7

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In general, the manuscript “The impact of CCR5, CCL5, PDGF, and EphA7 Levels on the Early Diagnosis of Gastric Cancer” is well written and overall provides a good summary and explanation of the data generated. It also points out the limitations and further strategies that can potentially implement the usability of these biomarkers in early diagnosis.  

However, one of my main questions is on the fact of “how do you know if these markers are predictive (diagnostic markers) or are overexpressed as a consequence of the cancer progression?”

Other questions and suggestions are in bold below following the paragraphs which the question has originated from:

Introduction:

                Platelet-derived growth factor-BB (PDGF-BB) protein is a homogenous disulfide bond dimeric ligand that binds to PDGF receptors. It plays an essential role in carcinogenesis. Among various isoforms of these proteins, PDGF-BB is effective in cell transformation and the growth and progression of tumors 

Can you give examples of cancer types where this protein is overexpressed?

Results:

                As far as we know, this is the first research that has examined the potential connection between GC and serum levels of PDGF, EphA7, CCR5, and CCL5. As a result, serum CCR5, EphA7, and especially PDGF-BB levels of the patients with GC were significantly higher than healthy individuals. Also, the outcomes obtained from the ROC analyses suggest that these molecule levels are valuable parameters with high accuracy in the early detection of GC. In addition, the study may extrapolate that CCR5, PDGF-BB, and EphA7 27may be helpful parameters in predicting survival.

It will be interesting to do a follow up study to monitor these markers for longer time and increase the sample size to include different populations/health centers.

Conclusions:

                There are some limitations of the study. Because it was a single-center study, a sufficient number of subjects could not be included. Hence, due to the small number of subjects and the non-homogeneous distribution of tumor-specific parameters such as tumor grade or stage of disease, the results of these analyses may suggest conflicting conclusions. As a natural consequence of the time constraints included in this study, no objective assessment was performed on the predictive value of the parameters examined for the early detection of GC in healthy individuals.

 Is a good point it is a very narrow population for the analysis. It’s hard to extrapolate into other groups and to draw general conclusions on the usage of such markers as diagnosis tools.

 

My Overall recommendation is to Accept in the present form.

Author Response

Comments:

Response: Agree. We have, accordingly, revised the study.

Reviewer 2 Report

Comments and Suggestions for Authors

I have carefully reviewed the manuscript titled “The Impact of CCR5, CCL5, PDGF, and EphA7 Levels on the Early Diagnosis of Gastric Cancer.” This study addresses an important and timely topic, focusing on the identification of potential serum biomarkers for early gastric cancer (GC) diagnosis, which could significantly enhance patient outcomes. The investigation of CCR5, CCL5, PDGF-BB, and EphA7 levels in GC patients is novel and contributes to the growing body of literature on cancer diagnostics. The study’s strengths include the use of appropriate statistical methods and its clear presentation of findings. However, certain aspects, including sample size considerations, control group matching, and the depth of the discussion, could be improved for clarity and completeness. I provide detailed feedback below to enhance the rigor and impact of this research.

 

Title

The title could be made more concise by avoiding listing multiple biomarkers, which may overwhelm readers. For example, you could condense the title to something like: “The Role of Biomarkers in Early Diagnosis of Gastric Cancer: A Study on CCR5, CCL5, PDGF, and EphA7.”

 

Abstract

1. While the study’s goal is stated, a clearer description of the clinical or research gap would be helpful. For example, a short sentence explaining why current diagnostic methods for GC are inadequate could strengthen the rationale.

2. Although the ELISA method is mentioned, a brief explanation of the reasoning behind selecting CCR5, CCL5, PDGF, and EphA7 as biomarkers would be helpful in the abstract to enhance understanding of the biological relevance.

3. The inclusion of statistical results is valuable; however, it might be more effective if there were a clearer emphasis on the most critical findings. While all four biomarkers are mentioned, highlighting PDGF-BB’s exceptional performance in diagnosis earlier in the abstract might sharpen the focus.

 

Introduction

1. The first two sentences could be more concise. The paper starts with general statistics, which is standard but could be condensed to focus more on the need for early diagnosis.

2. While the introduction covers a wide array of risk factors and biological mechanisms, it could emphasize more directly why CCR5, CCL5, PDGF-BB, and EphA7 were chosen as the focus. The text touches on their roles in other cancers but doesn't directly address their potential in gastric cancer until later.

3. The transition between general risk factors and the biomarker discussion (chemokines and growth factors) feels abrupt. Adding a sentence or two explaining why biomarker discovery is essential for improving early diagnosis would improve the flow.

 

Materials and Methods

1. Add a sentence specifying the criteria for the control group beyond "routine screening." For example, mention if they were matched for factors like age, gender, or any health-related variables.

2. Provide a rationale for the sample size, or if a power analysis was conducted, briefly mention it. This could strengthen the methodology by ensuring that the study design was statistically robust.

3. The study includes patients with both resectable tumors and advanced cancer, which could affect biomarker levels. While it's mentioned that blood samples were collected before surgery or chemotherapy, it would be useful to explain whether biomarker levels were compared between early and late stages of cancer.

4. There is a small typo in the text where "50 mL streptavidin-HRP" and "50 μLchromogenic reagents A and B" are mentioned. The unit should be μL, not mL, and there is no space between “50 μL” and “chromogenic.”

5. ROC analysis is mentioned as a method for evaluating the diagnostic usability of biomarkers. While this is an excellent approach, a brief explanation of how the cut-off values were chosen for ROC analysis would be valuable.

 

Discussion

1. Some of the sections, particularly regarding the CCL5/CCR5 axis, contain repetitive details on pathways and mechanisms already mentioned in the introduction or earlier in the discussion. This redundancy could be reduced to streamline the discussion.

 

2. Expand the limitations section to address potential selection bias (e.g., how patients were selected for the study), the absence of validation in an independent cohort, and the limited ability to generalize the findings to different populations or regions. Acknowledge the need for larger, multi-center studies to validate your findings. 

Comments on the Quality of English Language

Moderate editing of English language required.

Author Response

Comments 1: The title could be made more concise by avoiding listing multiple biomarkers, which may overwhelm readers. For example, you could condense the title to something like: “The Role of Biomarkers in Early Diagnosis of Gastric Cancer: A Study on CCR5, CCL5, PDGF, and EphA7.”

Response 1: Thank you for pointing this out. We agree with this comment. Therefore, we renewed the title of the article to be more prominent in line with your suggestion.

Comments 2: While the study’s goal is stated, a clearer description of the clinical or research gap would be helpful. For example, a short sentence explaining why current diagnostic methods for GC are inadequate could strengthen the rationale.

Response 2: Agree. We have, accordingly, added an explanation to emphasize the importance of early diagnosis in the abstract.

Comments 3: Although the ELISA method is mentioned, a brief explanation of the reasoning behind selecting CCR5, CCL5, PDGF, and EphA7 as biomarkers would be helpful in the abstract to enhance understanding of the biological relevance

Respose3: Agree, in line with your suggestion, the information that these biomarkers have been identified in the carcinogenesis of many cancers has been added to the abstract.

Comments 4: The inclusion of statistical results is valuable; however, it might be more effective if there were a clearer emphasis on the most critical findings. While all four biomarkers are mentioned, highlighting PDGF-BB’s exceptional performance in diagnosis earlier in the abstract might sharpen the focus.

Response 4: The abstract reported that PDGF-BB levels showed a better correlation in the gastric cancer group than healthy controls, the serum levels were higher, and the positive and negative predictive values were higher, especially.

Comments 5: The first two sentences could be more concise. The paper starts with general statistics, which is standard but could be condensed to focus more on the need for early diagnosis

Response 5: Agree. The first part of the introduction has been modified according to your suggestions.

Comments 6: While the introduction covers a wide array of risk factors and biological mechanisms, it could emphasize more directly why CCR5, CCL5, PDGF-BB, and EphA7 were chosen as the focus. The text touches on their roles in other cancers but doesn't directly address their potential in gastric cancer until later

Response 6: The roles of these biomarkers in gastric cancer development are discussed in the introduction

Comments 7: The transition between general risk factors and the biomarker discussion (chemokines and growth factors) feels abrupt. Adding a sentence or two explaining why biomarker discovery is essential for improving early diagnosis would improve the flow.

Response 7: Agree, Explanations that can provide the connection you mentioned have been added to the introduktion.

Comments 8: Add a sentence specifying the criteria for the control group beyond "routine screening." For example, mention if they were matched for factors like age, gender, or any health-related variables.

Response 8: Thank you for pointing this out. We have, accordingly, modified.

Comments 9: Provide a rationale for the sample size, or if a power analysis was conducted, briefly mention it. This could strengthen the methodology by ensuring that the study design was statistically robust.

Response 9: WE didnot do a power analysis. In the start of study we wanted to do survival analysis. So we have to choose a date gap to take patients in the study. We took all the patient suitable for this study in these period.

Comments 10: The study includes patients with both resectable tumors and advanced cancer, which could affect biomarker levels. While it's mentioned that blood samples were collected before surgery or chemotherapy, it would be useful to explain whether biomarker levels were compared between early and late stages of cancer.

Response 10: Information regarding the non-discrimination or comparison of biomarker levels between early and late stages of cancer has been added to the method section.

Comments 11: There is a small typo in the text where "50 mL streptavidin-HRP" and "50 μLchromogenic reagents A and B" are mentioned. The unit should be μL, not mL, and there is no space between “50 μL” and “chromogenic.”

Response 11: Agree. Corrected in the text.

Comments 12: ROC analysis is mentioned as a method for evaluating the diagnostic usability of biomarkers. While this is an excellent approach, a brief explanation of how the cut-off values were chosen for ROC analysis would be valuable

Response 12: Cut off value is the difference where between the sensitivity and specificity values is minimum

Comments 13: Some of the sections, particularly regarding the CCL5/CCR5 axis, contain repetitive details on pathways and mechanisms already mentioned in the introduction or earlier in the discussion. This redundancy could be reduced to streamline the discussion.

Response 13: The identified part was tried to be organized

Comments 14: Expand the limitations section to address potential selection bias (e.g., how patients were selected for the study), the absence of validation in an independent cohort, and the limited ability to generalize the findings to different populations or regions. Acknowledge the need for larger, multi-center studies to validate your findings. 

Response 14: We have, accordingly, added an explanation to your suggestions.