Circulating tumor cell detection approaching to clinical application

As "seeds" of tumor metastasis, circulating tumor cell (CTC) has important clinical application value in early diagnosis, immunotherapy and prognosis evaluation of tumors. With a deep understanding of CTC, its applied research has switched from cell enumeration to the molecular typing and single-cell sequencing. However, the standardization of CTC detection is still at a primary stage, opportunities and challenges coexist. This paper will review the current status and challenges in clinical applications of CTC detection, and make some suggestions for future development. Key words: Neoplastic cells, circulating; Liquid biopsy; Genetic heterogeneity; Reference standards; Biomarkers, tumor