Cancer Stem Cells in Sarcomas: In Vitro Isolation and Role as Prognostic Markers: A Systematic Review

SIMPLE SUMMARY: Cancer stem cells (CSCs) are responsible for the great challenge in the treatment of sarcomas due to their high prediction to form metastases. This systematic review focuses on collecting existing research on the expression of CSC markers in different types of sarcomas in both in vitro cell lines and patient samples. The results show a great heterogeneity of the studied markers, with ALDH being the only marker commonly used in sarcomas. This broader view may help to develop new CSC characterization assays to advance in more personalized treatments. ABSTRACT: Sarcomas are a diverse group of neoplasms with an incidence rate of 15% of childhood cancers. They exhibit a high tendency to develop early metastases and are often resistant to available treatments, resulting in poor prognosis and survival. In this context, cancer stem cells (CSCs) have been implicated in recurrence, metastasis, and drug resistance, making the search for diagnostic and prognostic biomarkers of the disease crucial. The objective of this systematic review was to analyze the expression of CSC biomarkers both after isolation from in vitro cell lines and from the complete cell population of patient tumor samples. A total of 228 publications from January 2011 to June 2021 was retrieved from different databases, of which 35 articles were included for analysis. The studies demonstrated significant heterogeneity in both the markers detected and the CSC isolation techniques used. ALDH was identified as a common marker in various types of sarcomas. In conclusion, the identification of CSC markers in sarcomas may facilitate the development of personalized medicine and improve treatment outcomes.