The role of epithelial–mesenchymal transition in oral squamous cell carcinoma and oral submucous fibrosis

Epithelial–mesenchymal transition (EMT) is an indispensable mechanism during morphogenesis. Interest and research in EMT are currently at a high level due to its important role in cancer and fibrosis. Emerging evidence suggests that EMT is also a crucial event in oral squamous cell carcinoma (OSCC). Oral submucous fibrosis (OSF) is a chronic debilitating disease and a premalignant condition of the oral cavity. It is characterized by a generalized submucosal fibrosis. The pathogenesis of the disease is not well established. Epidemiological evidence strongly indicates an association between the betel quid (BQ) chewing habit and OSF. In a simplistic view, OSF represents a failed wound-healing process of the oral mucosa after chronic, sustained injury. This review highlights the signaling pathways involved in EMT, recent advances in the study of EMT in OSCC, and summarizes the evidence supporting a role for EMT in the pathogenesis of OSF.