Epithelial-mesenchymal transition (EMT) is a biological process where epithelial cells lose their cell polarity and adhesion, gaining migratory and invasive properties to become mesenchymal stem cells, which is crucial in development, wound healing, and cancer metastasis. EMT is regulated by a network of signaling pathways and transcription factors and involves changes in gene expression, cytoskeletal dynamics, and extracellular matrix composition.