The Microenvironmental Effect in the Progression, Metastasis, and Dormancy of Breast Cancer: A Model System within Bone Marrow

Figure 1

The epithelial-to-mesenchymal transition (EMT) is a physiological process by which an epithelial cell loses polarity and assumes a mesenchymal phenotype. While EMT can occur naturally in gastrulation and wound repair, it is involved as a route of metastasis in cancer. Through molecular changes, such as the loss of E-cadherin, the epithelial cell undergoes remodeling and loosens its attachments from the basement membrane and adjoining cells to enter the vasculature. Once mobile, the malignant cells can take up residence at secondary sites, reverting to an epithelial cell type or remaining dormant.