The title of the paper is interesting and relevant since stem cell research has currently gained much interest with promising outcome. The regulatory effect of cytokines on stems cells needs further exploration since this subject is indispensable in the function and successful application of stem cells in regenerative medicine. This paper is therefore timely. However some concerns in the paper are pointed out below:

Major concerns 1. The abstract is poorly written and appears to contain only background information about the topic without any statement on the aim and objective of the study. An unstructured abstract should still be made up of the summary of background of the study, aims, methods (when applicable), findings, and conclusion. These elements are mostly lacking in the abstract making it difficult to understand and appreciate the scientific value of the work. 2. The reference are relevant to the topic and are well cited. However, approximately one-third of the reference are more than ten years, and one-fourth are papers in the 1990s. A review paper should focus mostly on recent finding, hence there is the need to replace most of these old references. 3. Insufficient references in the introduction/background; only two studies were cited in the entire introduction. Authors should include enough background studies and provide reference(s) to bold claims like “Cytokines regulate stem cell functions more than any other molecule” 4. Authors state that “This review is a concise overview of all the cytokines that affect proliferation, differentiation ...” This is the aim of the paper and appears to be overstated since authors cannot be sure that they covered “all cytokines”. This should be toned down. 5. Although authors did not mention how papers were selected for the review, it is generally accepted that, all facets of the topic should be sufficiently discussed. However, authors seem to focus mainly on bone marrow-derived or hematopoietic stem cells, and failed to mention studies on other important stem cells like adipose-derived, umbilical cord-derived, and induced pluripotent stem cells (iPSC). 6. To ensure adequate coverage of the topic, there should be a new heading to discuss the negative influence or inhibitory effects of cytokines on stem cells as a different variable measurement of the topic. 7. Findings should be well grouped and paragraphed for easy understanding of various concepts presented. 8. Authors do not add their personal views or discussions but only summarizes published papers. This makes the paper less interesting to read and lacks research direction and significance. I suggest that authors include precise but constructive discussions alongside the reported studies to help stratify what is already known, available research gaps, and the way forward. 9. There is no discussion section in the paper. This should be include to present the scientific significance of this review. 10. The summary introduces new statements like ‘stem cell can also produce different types of cytokines that can target various immune cells or the producer itself, in an autocrine manner’, which are not reviewed in this paper. Such new concepts/statements should be deleted or their purpose clearly stated.

Minor concerns 1. Acronyms used in the abstract are not defined. The only one defined was rather not defined on first appearance as expected.
2. Tittle should be given to table 1, and all abbreviations used should be defined. A reference column should be added to the table for easy inference, tracking, and a more complete information on each study. 3. There are few ‘,’ placement errors.