Carbohydrate changes in squamous cell carcinomas.

Cell surface carbohydrates serve as differentiation and development markers characteristic of different cell and tissue types. The expression of these carbohydrate antigens is often significantly altered in tumours, particularly in those arising from epithelial tissues. Analyses of cell surface carbohydrates in stratified epithelium have shown a remarkable variation in glycosylation pattern in relation to terminal differentiation. The carbohydrate expression is altered in squamous cell carcinomas and in premalignant lesions. There is evidence that the expression of certain carbohydrate structures in the deep invasive part of the tumours is correlated with tumour prognosis. The change in carbohydrate expression can at present be explained by the lack of synthesis of specific glycosyltransferases. New evidence suggests that the expression of certain carbohydrate structures may be importance for the formation of metastasies.