A very good paper on computational modelling for migration of cell clusters in 3D matrices. This paper looks at not a single but a cluster of cells migrating and their interaction with the extracellular matrix. The significance of this work lies in the fact that cell migration is an important part of the mechanisms for tissue repair, morphogenesis, and cancer invasion. Furthermore, different from their previous work the authors extend the analysis to the much more complicated situation of clusters of cell which of course reflects a much more realistic situation.