[Cancer stemness and circulating tumor cells].

The principle concept of cancer stem cells (CSCs) giving rise to the carcinogenesis, relapse or metastasis of malignancy is broadly recognized. On the other hand, circulating tumor cells (CTCs) also plays important roles in relapse or metastasis of malignancy, and there has been much focused on the association between CSCs and CTCs in cancer cases. The technical innovations for detection of CTCs enabled us to unveil the nature of CTCs. We now realize that CTCs isolated by cell surface antibodies, such as DCLK1, LGR5 indicated CSC properties, and CTCs with epitherial-mesenchymal transition(EMT) phenotype showed characteristics of CSCs.