niche as well as in treatment resistance. Unlike most reviews on the similar subject, the review also focused on the TME's involvement in tumor heterogeneity in head and neck cancer, which is thought to be the major cause of treatment resistance. Understanding the mechanisms of how heterogeneity arises could lead to effective personalized cancer therapy. (https://www.frontiersin.org/articles/10.3389/fcell.2021.660210/full) The review by Man et al. highlighted the importance of hematopoietic stem cell (HSC) niche, which is the microenvironment for the maintenance of stem cells, namely, the cellular components and cytokines in the bone marrow (BM) environment. Understanding the BM niche's role in maintaining normal HSCs is essential in understanding how blood cancer develops and in developing effective treatments. This review also provided the roles of BM niche in successful HSC transplantation, which is a life-saving procedure for many hematologic diseases, including leukemia as well as potentially effective therapeutic targets for leukemia. (https://www.frontiersin.org/articles/10.3389/fcell.2021.621214/full) Finally, Lv et al. reviewed mechanisms of liver cancer stem cell (LCSC) maintenance and survival from over 150+ articles. This comprehensive review covers from important signaling pathways, niche composition, the origin of LCSC to new developments in therapeutics targeting LCSCs. Liver cancer, notably hepatocellular carcinoma, is the leading cause of cancer-related deaths worldwide without effective treatments. Many of the important signaling pathways described in the article, including Wnt, STAT3, TGF-b, Notch, Hedgehog, and BMI1 are known to play important roles during embryonic development and normal physiology. The review underscored the similarity between the normal and cancer stem cell and the complexity of CSC biologic property that we still have much to learn. (https://www.frontiersin.org/articles/10.3389/fcell.2021.691410/full) While some progress has been made in the treatment for leukemia and solid tumors, such as breast cancer, we still have unmet challenges in improving overall survival and outcomes for common cancers, especially when diagnosed late, such as lung, colon, liver, brain, and head and neck cancers. These articles highlight the emerging evidence that stem cell-like or cancer stem cells may play important roles in cancer development, progression, metastasis, and treatment resistance. The next challenge for scientists investigating cancer stem cells is to delineate the differences between normal stem cells and cancer stem cells, which may enable scientists and clinicians to develop more effective cancer diagnostics and therapeutics.
5 Authors
- AA
Annette Affolter
Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
- AL
Anne Lammert
Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
- JK
Johann Kern
Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
- CS
Claudia Scherl
Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany
- NR
Nicole Rotter
Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Mannheim, Medical Faculty Mannheim, Heidelberg University, Germany