Undulation Instability of Epithelial Tissues
  Treating the epithelium as an incompressible fluid adjacent to a viscoelastic stroma, we find a novel hydrodynamic instability that leads to the formation of protrusions of the epithelium into the stroma. This instability is a candidate for epithelial fingering observed in vivo. It occurs for sufficiently large viscosity, cell-division rate and thickness of the dividing region in the epithelium. Our work provides physical insight into a potential mechanism by which interfaces between epithelia and stromas undulate, and potentially by which tissue dysplasia leads to cancerous invasion. 
Markus Basan, Jean-Francois Joanny, Jacques Prost, and Thomas Risler
physics.bio-ph cond-mat.soft physics.flu-dyn physics.med-ph q-bio.TO