E-cadherin is a transmembrane protein that mediates calcium-dependent cell–cell adhesion and plays a key role in maintaining the structural integrity of epithelial monolayers. Loss of E-cadherin expression or function contributes to tumor progression, and because cancers are characterized by loss of cellular adhesion and dissemination, the ability of E-cadherin to suppress tumor cell invasion was logically attributed to its adhesive properties. In the June 23 Journal of Cell Biology, Alice S. Wong and Barry M. Gumbiner at the University of Virginia present new evidence that questions this hypothesis and that suggests a different scenario (Journal of Cell Biology, 161:1191-1203, June 23, 2003).