Circulation tumor cell isolation and enrichment technologies

During cancer metastasis, tumor cells migrate from the primary tumor site and spread to distant tissue or organs through the circulatory system of the body. While it is challenging to track metastatic tumor cells, circulating tumor cells (CTCs) via liquid biopsy provide a unique and important opportunity for longitudinal monitoring of residual cancer diseases and progression, showing great potential to facilitate precision medicine in cancer patients. The enumeration and characterization of CTCs represent prognostic and predictive biomarkers, which can be used to monitor the response to and efficacy of various therapies. Along with molecular and cellular features of CTCs, this data can inform the detection of early micro-metastases and assess progression of advanced disease in a more sensitive manner than traditional imaging modalities, serving as a complementary approach with added value. Nevertheless, comprehensive multiomic analyses of CTCs at inter-cellular (cluster), single-cell, and subcellular levels to elucidate relevant CTC cancer biology, tumor immune ecosystem biology, and clinical outcomes have yet to be achieved, demanding multidisciplinary collaboration to advance the field. Complementary to the published chapter on multiomic analyses and functional properties of CTCs, this chapter summarizes key methods and integrated strategies in CTC isolation, highlighting an accelerated evolution in high-throughput analysis of CTCs.