Scatter factors and invasive growth

Scatter factors are unequivocal signals governing a genetic program that in cludes cell detachment, repulsion, protection from apoptosis, invasiveness of extracellular matrices and proliferation. This pleiomorphic response is defined as 'invasive growth.' Under physiological conditions, it leads to m orphogenic cell movements through the matrix, and-primarily-to ordered buil ding of epithelial tubules. Dysfunctions in invasive growth cause enhanced proliferation, uncontrolled migration into surrounding tissues, and failure to differentiate, events that foster tumour growth and invasiveness. Scatt er factors act through tyrosine kinase receptors that belong to the Met onc ogene family. Here we discuss how alterations of these receptors or of thei r signal transduction pathways are responsible for cancer onset and progres sion towards metastasis.