Circulating tumor cells in precision medicine: challenges and opportunities

The mutational and phenotypic landscape of tumors is dynamic, requiring constant monitoring of cancer patients to provide the most up-to-date and effective care. Circulating tumor cells (CTCs) obtained via liquid biopsy can provide tumor DNA, RNA, and protein information that can aid in the diagnosis, prognosis, and treatment of patients. There have been many recent studies and advances in using CTC enumeration, characterization, and expansion to provide personalized cancer treatment, validating the benefit of using CTCs as a biomarker in standard of care procedures. In this paper, we aim to summarize these advances, their limitations, and suggest future areas of study necessary to bring CTC analysis to clinics.