CHANGES IN THE EXPRESSION OF ALPHA(V) INTEGRINS IN ORAL SQUAMOUS-CELLCARCINOMAS

Integrins are cell surface adhesion molecules that regulate normal cel lular interactions; aberrant integrin expression is believed to play a role in tumour invasion and metastasis. The alpha(v) subunit is capab le of forming heterodimers with several beta subunits but not all the heterodimers expressed in oral epithelium have been investigated. We h ave examined the distribution of alpha(v) integrins in normal buccal m ucosa and seventeen oral squamous cell carcinomas. Antibodies to the a lpha(v) subunit and alpha(v) beta(5) heterodimer stained normal epithe lium, with strong expression in the basal layers and weaker staining i n the more superficial layers. The beta(3) and beta(6) subunits were n ot expressed in normal epithelium. Anti-alpha(v) and anti-alpha(v) bet a(5) antibodies stained all the squamous cell carcinomas, but the patt ern of expression was variable both within and between tumours. Poorly differentiated tumours showed the weakest staining and often had area s showing loss of expression. beta(6) was expressed in all of the carc inomas, indicating new expression of the alpha(v) beta(6) integrin in malignant oral epithelium. These results suggest that alterations in a lpha(v) integrins may contribute to the behaviour of malignant epithel ium and that alpha(v) beta(6) expression may play a role in tumour pro gression.