Consequently, ectopic expression of OPG significantly enhanced the migration/invasion abilities and increased the expression of several mesenchymal markers (N-cadherin, Vimentin, Snail, and Twist1), and reduced the expression of the epithelial markers (E-cadherin and EpCAM) in mammary luminal cells as well as BC cells grown as 3D. This evidence concerns the gene EPCAM and breast cancer.