[Research progress of circulating tumor cells: the way from counting to subtyping].

Although circulating tumor cells(CTCs) have long been identified, it was not until the approval of CellSearch® system that CTCs are current lyunder in-depth investigation.The CTCs technology has advanced from simple cell counting into era of molecular subtyping. The development of sequencing technologies and liquid biopsy has made it possible to sequence single cell genomes. In the recent years, how to take advantage of CTCs as a useful tool to clarify the mechanisms of carcinogenesis and cancer development and to predict the patient survival have become a hot issue.