Figure 1.

The multicellular spheroid (MCS) formation process is divided into three stages. In the first stage, the extracellular matrix (ECM) acts as a long link head, and the scattered single cells form loose aggregates under the action of integrins. In the second stage, the epithelial cadherin accumulates, and the aggregates enter the delayed phase of suspension of compaction. In the third stage, the loose cell aggregates form dense spheroids under the strong hemophilic interaction of epithelial cadherin.