Circulating Tumor Cells: Emerging Frontiers in Cancer Technology

Circulating tumor cells (CTCs) are unique cells that originate from the main tumor site.They circulate in the bloodstream, and are implicated in metastasis, immune evasion and recurrence in various cancers.Associated biomarkers of importance for CTC detection include epithelial cell adhesion molecule (EpCAM), human epidermal growth factor receptor 2 (HER2), programmed death ligand-1 (PD-L1), cluster of differentiation 45 (CD45), and other cancer-specific biomolecules.Their role as standalone biomarkers, especially in the case of EpCAM, have been thoroughly examined in processes such as CTC detection, isolation and targeting.However, recent advances have determined that such biomarkers are more reliable when associated with secondary biomarkers, due to concerns regarding immune evasion and low sensitivity.Detection and isolation techniques rely on inclusion and exclusion of cell specific biomarkers.The identification of these molecules has fast-tracked the development of several groundbreaking technologies.This review collates key findings on CTC characteristics and biomarker identification.The most recent CTC isolation and detection technologies are discussed, with individual approaches based on inclusion and exclusion have also been discussed.Several emerging treatments that may also greatly benefit from CTC integration, including nanocarrier-mediated drug delivery, have been analyzed.Additionally, we have discussed the shortcomings in the current landscape, encompassing both physical barriers and research barriers.