The collective–amoeboid transition (CMT) is a process by which collective multicellular groups dissociate into amoeboid single cells following the down-regulation of integrins. CMTs contrast with epithelial–mesenchymal transitions (EMT) which occur following a loss of E-cadherin. Like EMTs, CATs are involved in the invasion of tumor cells into surrounding tissues, with amoeboid movement more likely to occur in soft extracellular matrix (ECM) and mesenchymal movement in stiff ECM. Although once differentiated, cells typically do not change their migration mode, EMTs and CMTs are highly plastic with cells capable of interconverting between them depending on intracelluar regulatory signals and the surrounding ECM.
CATs are the least common transition type in invading tumor cells, although they are noted in melanoma explants.