Circulating tumor cells ( CTCs ) exists in peripheral blood of patients with a variety of malignant tumors , the accurate detection of CTCs helps early detection of cancer , and can be used to guide individualized treatment of cancer patients , rapid assessment of tumor chemotherapy drugs and detection of tumor recurrence .However , the CTCs in peripheral blood of cancer patients were extremely low , their detection requires efficient and specific enrichment and separation methods .The new microfluidic technology can accurately control the microliquid preciously , combined with the immunomagnetic separation technology , has been applied in detecting CTCs , which can save the blood samples of CTCs , has the advantages of simple operation , fast sorting speed , high specificity and high purity .