EMT is the process by which epithelial cells, characterized by well-developed intercellular contacts, transdifferentiate into motile and invasive mesenchymal cells. This process is associated with the loss of transmembrane intercellular adhesion molecule E-cadherin and disruption of cell-cell junctions along with acquisition of migratory properties. EMT is integral in embryonic development, wound healing, and stem cell behavior; however, its aberrant activation by micro-environmental alterations and abnormal stimuli can lead to cancer progression. Here, we review the different molecular changes associated with EMT that are responsible for downregulation of epithelial genes. Increased knowledge of the EMT process is essential for therapeutic targeting of cancer cells.