CTC (Circulating Tumor Cell)

A circulating tumor cell (CTC) is a tumor cell that has entered the bloodstream from a primary or metastatic site.

To seed distant metastases, CTCs must survive three lethal bottlenecks in circulation — shear stress, immune surveillance, and anoikis — and a 2026 review argues this survival is driven by a shared phenotypic-plasticity axis along the epithelial–partial EMT–mesenchymal continuum, rather than by three unrelated mechanisms.