Cell invasion through basement membranes: an anchor of understanding.

To metastasize, cancer cells must acquire the ability to breach several basement membrane barriers. Cell invasions through basement membranes also occur during normal development and immune system function, enabling organ formation and cell dispersal. The mechanisms that cells use to cross basement membranes in vivo remain elusive. In cancer and development, these invasions occur in complex and inaccessible environments, which are difficult to study in vivo. Anchor-cell invasion in Caenorhabditis elegans is a simple, visually and experimentally accessible model of basement membrane invasion that is beginning to reveal a network of cellular and molecular control mechanisms that regulate the fundamental cellular process of invasion through basement membranes.