Anoikis

Anoikis (Greek for “homelessness”) is the programmed, apoptotic death that normal epithelial and endothelial cells undergo when they lose attachment to the extracellular matrix (ECM). It acts as a natural barrier against ectopic growth, invasion, and metastasis — a cell that detaches from the ECM but fails to die is instead described as anoikis-resistant.

For circulating tumor cells (CTCs), anoikis is one of three lethal bottlenecks — alongside shear stress and immune surveillance — that must be survived in the bloodstream in order to seed distant metastases.