Before revision:  Many existing mathematical models of cell polarization are formulated in  one or two spatial dimensions and hence cannot accurately capture the effect of cell shape, as well as the response of the cell to signals from different directions in a three-dimensional environment.
After revision:  Many existing mathematical models of cell polarization are formulated in terms of reaction-diffusion systems of interacting molecules, and are often defined in one or two spatial dimensions and hence cannot accurately capture the effect of cell shape, as well as the response of the cell to signals from different directions in a three-dimensional environment.