Review for 10.1186/s12876-025-04003-w (2025)

Title: Helicobacter pylori is associated with less tumor-infiltrating lymphocytes and a poor
prognosis in gastric cancer
Version: 2 Date: 10 Mar 2025
Reviewer:  Anwar Ashraf Abouelnasr
Reviewer's report:
Dear Authors, please address the following points below
-While the paper presents the association between H. pylori and TILs in the TME, there is a
limited mechanistic discussion on how H. pylori may modulate the immune response specifically
within the tumor environment. Understanding the molecular or cellular pathways by which H.
pylori impacts TILs or the immune checkpoint pathways could enhance the paper’s depth and
scientific contribution.
-The authors mention that H. pylori can resist immune responses through various mechanisms
like interfering with antigen recognition or increasing genetic variation. However, more detailed
molecular insights into these processes could provide greater understanding.
-It would be valuable to include a control group of patients without H. pylori infection, especially
since the study focuses on the association of H. pylori with TILs and prognosis. A direct
comparison between infected and non-infected groups could strengthen the conclusion regarding
the impact of H. pylori infection on GC prognosis and immunotherapy response.
-Additionally, comparing the immune profiles of patients with different types of gastric cancer
(e.g., those with and without H. pylori infection) could offer more clarity on the disease
heterogeneity.
-The study is limited to patients from a single center, and while the sample size may be adequate
for the statistical methods used, the external validity may be a concern. The generalizability of
the findings to other populations or settings is not addressed in the manuscript.
-Expanding the sample size or conducting multi-center studies would strengthen the findings
and allow for more robust conclusions that could be applied to a wider population.
Although the use of two independent pathologists to evaluate the IHC staining results is a good
practice, there is no clear mention of how inter-observer variability was assessed. It would be
important to note how any disagreements were handled beyond using a third pathologist for re-
evaluation.
-The scoring system used for TIL evaluation (e.g., CD3 and CD8 expression cutoff values) is
subjective. A more detailed discussion of how these thresholds were determined or validated
would improve the rigor of the methodology.
-The manuscript mentions PD-L1 as a key factor in immune evasion, but the relationship
between H. pylori infection and PD-L1 expression in GC is not clearly outlined. While there is
mention of PD-L1 as a target of immune checkpoint inhibition, it would be useful to provide
more data or discussion on how H. pylori might modulate PD-L1 expression specifically in the
context of GC.
-The Kaplan-Meier survival analysis conducted using KMplot software is based on public
microarray datasets, but the manuscript could further explain how these datasets relate to the
study population. It would be beneficial to see a more direct correlation between the findings
from the local patient cohort and the public dataset.
-While the discussion mentions Cox regression and survival analyses, the rationale behind
choosing these specific methods and their results could be elaborated further. For instance, the
authors could explain in more detail how the multivariate Cox regression was conducted and
why it did not show the same results as the univariate analysis. This would provide a clearer
understanding of the statistical approach and its implications.
-While the study mentions confounding factors in the multivariate analysis, there is little
discussion on how these factors were controlled or their potential impact on the results. A more
in-depth exploration of potential confounders (e.g., age, comorbidities, treatment regimens) and
how they might influence the findings would strengthen the argument.
-The discussion references the use of immunohistochemistry (IHC) to assess H. pylori status
but does not provide much detail about how the IHC results compare between H. pylori-positive
and negative patients, especially in terms of TIL infiltration and PD-L1 expression. Including
specific findings from IHC could provide more evidence to support the conclusions drawn from
the immunological analysis.
-While the recommendation for H. pylori eradication is sound, the discussion does not provide
much detail on the potential outcomes of H. pylori eradication in GC patients undergoing
immunotherapy. A discussion of the evidence for how H. pylori eradication might specifically
improve immune responses or survival in the context of immunotherapy could enhance the
clinical relevance of the study.
-The discussion could benefit from a more detailed exploration of the specific molecular
mechanisms by which H. pylori influences the immune microenvironment. For instance, further
elaboration on how H. pylori interacts with specific immune checkpoints or cytokine profiles in
the context of GC would add depth to the current understanding.