Efficient Isolation and Accurate In Situ Analysis of Circulating Tumor Cells Using Detachable Beads and a High-Pore-Density Filter

摘要

Circulating tumor cells (CTCs) in the bloodstream of cancer patients may indicate the likelihood and severity of metastatic progression. Identification, enumeration, and characterization of CTCs may provide a minimally invasive method for assessing cancer status of patients and prescribing personalized anticancer therapy. However, examination of CTCs requires isolation of these cells from whole blood of patients, which is difficult owing to their low quantity (around one CTC per 10~9 non-cancerous hematopoietic cells in patient blood). Many techniques are used to isolate CTCs, including density gradient centrifugation and dielectrophoresis, but methods using either size-based exclusion or affinity-based enrichment are common. Size-based exclusion assumes that CTCs are larger than most hematopoietic cells and removes all cells smaller than a pre-determined size threshold. Affinity-based enrichment relies on the expression of surface proteins specific to cancer cells and absent in hematopoietic cells. These methods generally use antibody-conjugated magnetic beads and enrich for CTCs by magnetic separation, such as the CellSearch system.