Micro-/nanotechnology-based isolation and clinical significance of circulating tumor cells

Circulating tumor cells (CTCs) are extremely rare in peripheral blood, and they are mostly derived from primary and metastatic epithelial tumors. Recent studies have reported that the presence of CTCs is an independent predictor of progression-free survival and overall survival of metastatic cancer patients, and is proportional to the progression of the disease when a carcinoma recurs. Because of the extremely low concentration of CTCs in peripheral blood (1–2 per 10 billion blood cells), the isolation and characterization of CTCs are major technological challenges. Recent micro-/nano-based technical advances are providing new opportunities for the isolation of purer CTCs from peripheral blood and better cellular and molecular characterization. This review focuses on available micro-/nano-based techniques for the detection of CTCs, clinical utilities of CTCs and their limitations, and future perspectives in this field.