Review for 10.1186/s12876-022-02205-0 (2022)

Title: Correlation and Prognostic Implications of Intratumor and Tumor Draining Lymph Node
Foxp3+ T Regulatory Cells in Colorectal Cancer
Version: 1 Date: 05 Jan 2022
Reviewer's report:
This study determined the correlation between T regulatory cells (Tregs) in tumors and tumor
draining lymph nodes (TDLNs) and examined their prognostic value. 150 colorectal cancer
(CRC) patients with radical primary lesions were analyzed, Tregs were detected in tumor
and TDLNs by immunohistochemical staining and counted in five hot spots. This study
showed a significant correlation between intratumor and TDLN Tregs. Only intratumoral Tregs
showed a significant prognostic value for patient survival. This article is meaningful because
this study showed the correlation between the number of Foxp3+ cells in tumor and that
in TDLNs of colorectal cancers, and their relationship to prognosis based on the results of
immunohistochemical staining of 150 cases.
Major issues
#It would be better to have more discussion on what makes Treg a favorable prognostic factor
in colorectal cancer patients, compared to other cancers. It seems insufficient to cite previous
papers that Treg releases inflammatory cytokines as a discussion. It is important to consider
whether there are any factors that are influenced by the methods and patients of this study.
#In this study, the absolute number of Treg was evaluated based on the results of
Immunohistochemical staining of Foxp3. It is generally recognized that Treg is suppressive to
immune cells. Therefore, the number of all immune cells is also an important factor. Shouldn't
the ratio of Treg numbers in immune cells be examined? If the absolute number of Treg is high
and the number of effector T cells is higher, anti-tumor immunity could be strong. How about
examining the ratio of Treg in CD3+ cells?
#FOXP3+ cells were counted in 5 hotspots, and the number of Treg cells was 0 in 26 (intratumor)
and 18 (TDLNs) out of 150 cases. Are there cases in which there are no Treg cells in the tumor
at all? And do such cases exist in more than 10% of cases? Since it is a high percentage, I think
it is necessary to include the reason for this in the discussion.
#The patients with distant metastases (M1) were included in the analysis of PFS, but these cases
should be excluded from the analysis. Did these cases achieve R0 resections with the distant
metastases?
#In the discussion, it is stated that "In the present study, we found that Tregs accumulated
heterogeneously in tumors and TDLNs.“, but what results lead to the conclusion of
"heterogeneously"?
Minor issues
#In patients and methods, it is stated that "The absolute number of Tregs in the tumor and
in TDLNs was counted", but how did you count the Treg? It would be better to describe the
counting method in more detail.
#In the discussion, there is a sentence "“It was reported that Tregs could not only release
inflammatory cytokines such as interleukin (IL)-10, IL-35, tumor necrosis factor-#, and
interferon-# [41,49] but also suppress other cytokine-producing cells such as myeloid dendritic
cells [50].”, but the cited article [41] states that Treg does not release inflammatory cytokines.
Is this citation correct?