CDH5 and breast cancer: Moreover, while integrating into the endothelial monolayer, VE-cadherin positive breast cancer cells showed a behavior indicative of a multistep process: first, tumor cells incorporate into the endothelial monolayer without affecting endothelial VE-cadherin localization at the tumor cell-endothelial cell contacts; then, VE-cadherin is displaced from these contacts, leading to the formation of gaps that allow the passage of tumor cells.