Аннотация:Mathematical modeling of the development of spherically symmetrical structures in a cell aggregate surrounded by a viscous extracellular matrix was performed. The problem statement uses our previously developed multiphase continuum model of a biological medium formed by two actively interacting solid phases and a liquid. One of the solid phases is formed by cells, the other by the extracellular matrix. The change in the radius of the spherical surface bounding the aggregate is determined by conditions that take into account the redistribution of the load between the cell phase and the matrix phase on opposite sides of the aggregate boundary. The influence of active interactions of cells both among themselves and with the matrix, as well as the initial composition of the cell aggregate on the process of redistribution of the volume concentrations of cells and matrix, was studied. Processes associated with cell division and the production of prote-olytic enzymes are not considered. Numerical calculations have shown that in the case of dominance of intercellular active mechanical interactions over cross interactions be-tween cells and the matrix, only compaction of both loose and dense aggregates occurs non-invasive development. In the case of dominance of active cross interactions over intercellular ones, the scenario of the development of cell structures depends on the initial volume concentration of cell phase. In loose aggregates, a heterogeneous distribu-tion of the concentration of the cell phase is formed, which under certain conditions can develop into a hollow cell structure. In dense aggregates, a dense core is formed and part of the cell phase detaches from the main mass.