108 страниц. 2010 год. LAP Lambert Academic Publishing The expression of simple epithelial cytokeratins 8 and 18 is normally seen in the embryonic cells and lost in adult squamous epithelium. CK 8 and 18 play a role in tumor progression and metastatic potential as these are expressed only in the poorly differentiated and not in well differentiated squamous cell carcinomas. It appears that increased expression of the embryonic or simple epithelial cytokeratins 8 and 18 in some way changes the phenotypic characteristics of stratified epithelial cells, resulting in malignant transformation. Presence of Cytokeratin 8 and 18 in poorly differentiated foci of Oral squamous cell carcinoma even in the absence of metastasis could indicate a poor prognosis in these patients. However they are of functional importance in malignancy of keratinocytes and could be related to tumor invasion and/or to changes in epithelial mesenchymal interactions.