The great escape: when cancer cells hijack the genes for chemotaxis and motility.

The combined use of the new technologies of multiphoton-based intravital imaging, the chemotaxis-mediated collection of invasive cells, and high sensitivity expression profiling has allowed the correlation of the behavior of invasive tumor cells in vivo with their gene expression patterns. New insights have resulted including a gene expression signature for invasive cells and the tumor microenvironment invasion model. This model proposes that tumor invasion and metastasis can be studied as a problem resembling normal morphogenesis. We discuss how these new insights may lead to a better understanding of the molecular basis of the invasive behavior of tumor cells in vivo, which may result in new strategies for the diagnosis and treatment of metastasis.