Review for 10.1186/s12876-024-03260-5 (2024)

Title: Evaluating the Diagnostic Accuracy of Heat Shock Proteins and their Combination with
Alpha-Fetoprotein in the Detection of Hepatocellular Carcinoma: A Meta-Analysis
Version: 1 Date: 13 Nov 2023
Reviewer:  Zaki A. Sherif
Reviewer's report:
Please refine the title for clarity. For example: “Evaluating the Diagnostic Accuracy of Heat
Shock Proteins and their Combination with Alpha-Fetoprotein for Hepatocellular Carcinoma
Detection: A Meta-Analysis".
Line 56: “…cancer-related deaths were occurred worldwide”. Please take out the word “were”.
Line 59: “…diagnosed at an advanced stage for the lack of typical clinical symptoms and signs”.
Add “early” before “signs”.
Line 60: “…the 5-year survival rate is seriously poor”. It would echo the urgency of the condition
if you rephrased it as “The 5-year survival rate is notably dismal.”
Line 63: “…are the most commonly used methods. Just take out the word “commonly”.
Line 69: “…Ultrasonography is more widely available and affordable than other imaging
methods, although accuracy of liver ultrasonography is limited due to the methodological
factors? First, it would be better to use “constrained by” and not “limited due to” methodological
factors. Secondly, what is meant by “methodological factors”. You need to specify and clarify
these methodological factors” that may limit the accuracy of liver ultrasonography. For example,
you might elaborate on issues related to image resolution, operator skill and subjectivity, or
patient factors.
Line 96 should read “we conducted this systematic review” not “system review”.
Note: From this point forward, I will refrain from addressing grammatical corrections and will
concentrate on evaluating the content of the paper. However, I recommend having someone
review the English before resubmitting it.
Lines 11-112: “Additional eligible articles in the references list were obtained by manual
searching.”. It would be more specific if you wrote “Additional eligible articles were identified
by manually searching the references of included studies."
In the inclusion criteria, you might want to clarify whether the studies had to include both HSPs
and AFP in their evaluations or if studies solely focused on either HSPs or AFP.
Lines 132-133: The description of the QUADAS-2 tool is clear. However, it might be helpful
to provide a brief explanation of why the QUADAS-2 tool was chosen and why it is considered
reliable for assessing the quality of diagnostic accuracy studies.
The results section does not provide enough details about the quality evaluation of the included
studies. The authors should report the quality scores of each study and explain how they assessed
the risk of bias and heterogeneity. I see that in Figures 1, the authors did try to qualitatively
address my concerns by providing a figure to summarize the quality assessment results even
though the scores were not tallied for each of the 8 articles selected.
In the key terms of Table 1, you should also indicate that “Sen” stands for sensitivity and that
“Spe”, for specificity. Be consistent. Also, in this section, there is no explanation as to why the
sensitivity and specificity of HSPs and AFP are similar, despite the different biological roles and
mechanisms of these biomarkers. I hope the authors will provide (even if it is in the Discussion
section) some possible reasons or hypotheses for this observation, based on the existing literature
or their own data analysis.
Lines 178-190: The results section does not report the confidence intervals for the pooled DOR
and AUC, which are important measures of the diagnostic accuracy and precision of HSPs and
AFP. The authors do include these values in figures but not in the write-up section of the Results.
I hope to see that they will discuss how they compare with other studies or meta-analyses.
Furthermore, even though Figure 1 displays the biases of the eight studies and Table 1 shows
the different methods used by the eight studies, the authors do not address the potential sources
of heterogeneity and the different cut-off values, the different stages and etiologies of HCC,
and the different quality of the studies. The authors should perform subgroup analyses or meta-
regression to explore the effects of these factors on the diagnostic performance of HSPs and
AFP. After mentioning the subgroup analysis based on control population and case number,
they can provide a brief summary or key findings from the subgroup analysis to guide readers
through the results more efficiently.
To the authors’ credit and according to their analyses, the combination of HSPs and AFP has
a high sensitivity and specificity for diagnosing HCC, which means it can correctly identify
most of the true positive and true negative cases. The combination also has a high positive
likelihood ratio (PLR) and a low negative likelihood ratio (NLR), which means it can increase
the probability of having HCC when the test is positive and decrease the probability of having
HCC when the test is negative. The combination also has a high diagnostic odds ratio (DOR),
which measures the overall diagnostic performance of the test. The area under the SROC curve
(AUC) is close to 1, which indicates a high accuracy of the test. The combination of HSPs
and AFP outperforms HSPs or AFP alone in all these indices, suggesting that it may be a
superior diagnostic method for HCC based on this meta-analysis. Highlighting any observed
synergistic effects or improvements in diagnostic accuracy should help garner support for using
this combination diagnostic test for HCC.
Another point is that the results section does not provide enough details about the heterogeneity
and subgroup analysis as I indicated before. The authors should explain how they calculated
the I2 statistical parameters and why they chose a cut-off value of 88.9% to indicate significant
heterogeneity. An explicit explanation of these values could help readers understand the degree
of variability.
I got confused when the authors repeated the Spearman correlation coefficient and P-value for
each category (HSPs, AFP, and combination of both). I wish they would consider presenting
them in a single sentence to enhance clarity and reduce repetition. Another confusion is found
at the end of your Results section where you mention the Deek's Funnel Plot Asymmetry Test.
Readers but not necessarily reviewers like me need a brief explanation of Deek's funnel plot
asymmetry test and its implications for detecting publication bias. This would aid readers who
may not be familiar with this statistical test.
Finally, the discussion section needs some more critical analysis of the main findings and their
implications. I appreciate the fact that the authors decided to transition successfully to the
focus on heat shock proteins (HSPs), highlighting their performance as diagnostic biomarkers in
various cancers, including HCC, for which they provided a nuanced perspective on its suitability
as a biomarker for early HCC detection. The discussion rightly also underscores the significance
of combining biomarkers for enhanced diagnostic accuracy. It references recent meta-analyses
that explore combinations like AFP with DCP, GPC-3 with AFP, and AFP with AFP-L3 and
DCP. Of course, what makes this meta-analysis unique in this regard is the inclusion of HSP
among these dual diagnostic testing mechansims.
While the discussion mentions several limitations, such as the geographical bias (i.e.,
disproportionately in China) in the included studies, the case-control study design, and the
inconsistency in cut-off values, it does not provide a more in-depth discussion on the clinical
implications of these limitations and potential avenues for improvement in future research.
Furthermore, the discussion does not discuss the clinical implications and applicability of HSPs
and AFP combination in HCC diagnosis overall, such as the cost-effectiveness, availability, and
feasibility of the test, and the impact on patient outcomes and management.
I also don’t think the authors discussed or considered the possible confounding factors that may
affect the expression and detection of HSPs and AFP, such as the stage, grade, and etiology
of HCC, the coexistence of other liver diseases, and the treatment history of the patients. The
articles they analyzed might not have considered these factors, but this meta-analysis should
have thoroughly addressed and accounted for these potential confounding factors to ensure a
more comprehensive and reliable assessment of the diagnostic accuracy of HSPs and AFP in
HCC.