Can alterations in integrin and laminin-5 expression be used as markers ofmalignancy?

Development of squamous cell carcinomas (SCCs) involves alterations in the adhesive interactions in the epithelium and invasion through the basement m embrane. Therefore, changes in the expression of receptors and ligands invo lved in cell-cell and cell-matrix adhesion may be essential for the transfo rmation of a premalignant into a malignant lesion, The aim of this study wa s to examine if expression of specific cell adhesion molecules can be used as markers of malignant development. By immunohistochemistry, we examined t he expression pattern of integrins alpha 2 beta 1, alpha 3 beta 1, alpha 6 beta 4 and laminin-5 in biopsies from SCCs (n=18), premalignant lesions (le ukoplakias, n=21) and non-premalignant tissue with chronic inflammation (n= 11). In poorly differentiated SCCs, patchy loss of alpha 3 beta 1, alpha 6 beta 4 and laminin-5 expression was pronounced at the invasion front, where as there was a tendency to increased expression of alpha 2 beta 1. Analogou s to the SCCs, biopsies from the leukoplakias and the non-premalignant infl ammatory tissue showed alterations of the expression of alpha 3 beta 1 and alpha 6 beta 4 in the basal cell layers and of laminin-5. However, a charac teristic finding in biopsies from leukoplakias was loss of alpha 2 beta 1 a nd alpha 3 beta 1 in the suprabasal cells. There was no unequivocal express ion of the adhesion molecules distinguishing between inflammatory tissue, p remalignant, and malignant lesions.