Epithelial-mesenchymal (EM) interactions are a series of programmed, sequential and reciprocal (complex and multiphase) communications between the epithelium and mesenchyme (two heterotypic cell populations) resulting in the differentiation of one or both the cell populations involved. The role of EMIs can be best explained in oral tissues, due to the higher epithelial contribution to the development of oral anatomical structures. The role of EMIs in cancer is clearly understood in epithelial malignancies, due to the function of the basement membrane and the required angiogenic process in cancer.Epithelial mesenchymal interactions appear to play an important role in the formation and the maintenance of normal tissue architecture, whereas their dysregulation contributes to tumorigenesis.

Epithelial mesenchymal interactions plays one of the most integral part in oral and maxillofacial pathology. These interactions are involved in normal development of many organs as well as in tumorigenesis. A deeper insight and knowledge of such interactions helps in correlating the normal physiology and pathology.