Epithelial-Mesenchymal Transition Pathways in Breast Cancer

Epithelial-Mesenchymal Transition (EMT) is one of the key molecular mechanisms contributing to metastatic progression. This process is involved in the local invasion and migration of various cancers, including breast cancer. Changes in the EMT regulatory pathways during tumorigenesis lead to the loss of cellular adhesions, changes in the polarity of the cell and cytoskeleton, detachment of the cell, migration, intravasation, survival in the vascular system, extravasation, and, finally, metastasis. EMT is largely mediated by a core set of EMT-activating transcription factors. Many pathways are involved in the EMT regulation; the primary mediators include TGF, Notch, and Wnt. Several in vitro studies on normal and malignant mammary epithelial cells, as well in vivo studies on mouse models with breast cancer, have shown the role of EMT in this cancer. Investigation of the EMT regulatory pathways can help in cancer surveillance and treatment and make potential direct targets for new-combination anticancer drugs and personalized medicine.