Resumen
Metastasis is the main cause of cancer-related death. Circulating cancer stem cells have recently attracted attention because they have higher tumorigenicity than non-stem-like circulating tumor cells. Despite the strong scientific evidence for circulating cancer stem cells and secondary tumor formation, the exact mechanisms behind the generation and characteristics of circulating cancer stem cells are not yet fully understood because of their extreme scarcity. This review aims to introduce the recent advances in the detection and analysis of circulating tumor cells and circulating cancer stem cells.