Detection of Circulating Tumor Cells and Epithelial Progenitor Cells: A Comprehensive Study

Technological advancement to enhance tumor cells (TC) has allowed discovery of various cellular bio-markers: cancer stem cells (CSC), circulating tumor cells (CTC), and endothelial progenitor cells (EPC). These are re-sponsible for resistance, metastasis, and premetastatic conditions of cancer. Detection of CSC, CTC, and EPC assists in early diagnosis, recurrence prediction, and treatment efficacy. This review describes various methods to detect TC subpop-ulations such as in vivo assays (sphere-forming, serial dilution, and serial transplantation), in vitro assays (colony-forming cells, microsphere, side-population, surface antigen staining, aldehyde dehydrogenase activity, and Paul Karl Horan la-bel-retaining cells, surface markers, nonenriched and enriched detection), reporter systems, and other analytical methods (flow cytometry, fluorescence microscopy/spectroscopy, etc.). The detailed information on methods to detect CSC, CTC, and EPC in this review will assist investigators in successful prognosis, diagnosis, and cancer treatment with greater ease.

Automated summary

Technological advancement has enabled the discovery of various cellular biomarkers, including CSC, CTC, and EPC, which play crucial roles in cancer resistance, metastasis, and premetastatic conditions. Detecting these subpopulations assists in early diagnosis, recurrence prediction, and treatment efficacy. This review provides comprehensive information on different methods to detect CSC, CTC, and EPC, ranging from in vivo and in vitro assays to reporter systems and analytical techniques such as flow cytometry and fluorescence microscopy/spectroscopy.