Isolation and release of rare,pure and viable circulating tumor cells(CTCs)provides a significant advance in early cancer detection.However,the low occurrence of cancer cells in the bloodstream hampers the enrichment and characterization of CTCs.Thus,isolation of CTCs with high efficiency is urgently needed.At the same time,releasing captured CTCs while maintaining their viability for subsequent cell culture or molecular analysis is also important.Herein,we describe a new method of peptide-tagged antibody-based immunomagnetic CTC detection.In this assay,86% of cancer cells were specifically targeted by magnetic beads conjugated with peptide-tagged antibody and biotin could be added to release 70% of captured cells.The capture and release process rarely influence the viability and proliferation ability of cells.These results support that our method has great potential as an effective tool for CTC enrichment and diagnosis.