  Although a good comprehension of how cancer cells collectively migrate by
following molecular rules which influence the state of cell-cell adhesion
contacts has been generated, the impact of collective migration on cellular
rearrangement from subcellular to supracellular level remains less understood.
Thus, considering collective cell migration (CCM) of cancer mesenchymal cells
on one side and healthy epithelial cells on the other during the fusion of two
cell aggregates could result in a powerful tool in order to address the
contribution of structural changes at subcellular level which influence the
cellular rearrangements and help to understand this important, but still
controversial topic. While healthy epithelial cells undergo volumetric cell
rearrangement driven by the tissue surface tension, which results in a
collision of opposite directed velocity front near the contact point between
two cell aggregates, mesenchymal cells follow quite different scenario. These
cells are capable of reducing the surface tension and undergo surface cell
rearrangement. The main goal of this contribution is to discuss the origin of
surface activity of cancer cells by accounting for the crosstalk between
cell-cell and cell-ECM adhesion contacts influenced by the cell contractility.
