Review for 10.1186/s12876-025-03645-0 (2025)

Title: Collagen turnover biomarkers to predict outcome of patients with biliary cancer
Version: 2 Date: 27 Dec 2024
Reviewer:  Anwar Ashraf Abouelnasr
Reviewer's report:
Dear Authors, please address the following points below
-While the introduction does an excellent job of explaining the roles of different collagens in
the ECM, some readers without a strong background in molecular biology may find the detailed
description of the various collagen types and their specific roles a bit dense. Consider briefly
simplifying the explanation or providing more context to clarify why these particular collagen
types were chosen for this study.
-Terms like "desmoplastic tumor stroma" and "protease-driven collagen turnover" are used
without much further elaboration. While these concepts are likely familiar to an expert audience,
some explanation of these processes in layman's terms could make the text more accessible,
especially for interdisciplinary readers.
-The introduction could benefit from a clearer flow between different sections. For instance,
the transition from the discussion of traditional biomarkers (CA 19-9, CEA) to the rationale
for studying collagen turnover biomarkers feels slightly abrupt. A sentence that bridges the gap
between these two sections could improve readability.
-The explanation of collagen turnover markers (e.g., reC1M, C3M, PRO-C3, etc.) is somewhat
detailed, but it would be useful to more explicitly connect each marker to the specific ECM role
it reflects (e.g., collagen degradation vs. synthesis) to reinforce why each was chosen.
While the introduction mentions various collagen types and the rationale for using them as
biomarkers, it could benefit from a brief mention of the literature on the role of these specific
biomarkers in other cancers, if available. This would help to contextualize the study in a broader
research landscape.
-The explanation of how the different collagen turnover markers are released during collagen
remodeling could be slightly more integrated into the discussion of the biomarkers studied. For
example, connecting PRO-C3 and PRO-C8 with their specific collagen degradation processes
could help clarify why they are particularly relevant for BTC.
-While the discussion includes useful references to p-values and statistical significance (e.g.,
for OS and PFS), there could be more emphasis on how the results were analyzed in relation to
the control group. For example, the authors mention that "none of the markers was constantly
downregulated after first and second CTX," but a more detailed explanation of how these trends
were quantified and interpreted would help clarify the statistical robustness of this statement.
-In addition, the authors note that no adjustments for multiple testing were performed. While
this is a valid point, a brief discussion of the potential impact of this limitation on the findings
would be useful for the reader. Without adjustments for multiple comparisons, some of the p-
values could be false positives.
-The authors mention that C4G was mildly upregulated in the early stages of BTC and caution
that this finding needs to be interpreted with caution. It would be helpful to elaborate on why
C4G was the only marker that exhibited this stage-specific change, especially given that the other
markers (e.g., PRO-C3, PRO-C8) did not show significant stage-related variations. The potential
biological or clinical implications of this finding, even if preliminary, could be discussed further.
-The authors do a good job of explaining the relevance of type VIII collagen, particularly in the
context of the basement membrane and cancer-associated fibroblast (CAF) activity. However,
more could be said about the specific role of PRO-C8 in the ECM remodeling process in BTC.
While the study highlights PRO-C8's diagnostic and prognostic potential, a deeper dive into the
biological mechanisms behind its role in BTC and why it stands out as a key predictor of patient
outcomes would enrich the discussion.
-A potential direction for future research could also be suggested here, such as investigating how
PRO-C8 interacts with other elements of the TME or how it might be linked to specific BTC
subtypes or molecular profiles.