Tumor cell migration in three dimensions.

In almost all physiological and pathological situations, cells migrate through three-dimensional environments, yet most studies of cell motility have used two-dimensional substrates. It is clear that two-dimensional substrates do not mimic the in vivo environment accurately, and recent work using three-dimensional environments has revealed many different mechanisms of cell migration (Abbott, 2003; Sahai and Marshall, 2003; Wolf et al., 2003). This chapter will describe methods for generating three-dimensional matrices suitable for studying cell motility, methods for imaging the morphology of motile cells in situ, and methods for quantifying cell migration through three-dimensional environments.