Transition of normal oral mucosa to squamous cell carcinoma involves induction of [alpha]v[beta]6 integrin

• Main Author: Hamidi, Sara
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/6353

Integrins are a family of cell surface receptors that mediate cell-matrix adhesion. They are believed to be essential molecules involved in tumour cell invasion and metastasis. It has been shown previously that the αv β6 integrin, a fibronectin and tenascin receptor, is not expressed in normal tissues, but may be associated with malignancy. In this study, we have used immunohistochemical localization technique to examine the expression and distribution of αv β6 integrin in frozen sections of oral specimens representing 40 leukoplakia patients, 11 squamous cell carcinomas (SCCs), 5 hyperplasia, 8 lichen planus, 2 mucosal wounds, 3 periodontal pocket samples and 11 normal subjects. Integrins αv, β1, β3, β4, β5, B6, fibronectin, and tenascin were localized using specific antibodies. The expression of β 1 integrins was consistent throughout the basal layer, and that of the β4 at the cell surface facing the basement membrane of all tissues. The integrins β3 and β5 were both absent from all normal and leukoplakia tissue specimens. The integrin αv β6 was highly expressed throughout the whole lesion of 90% of the SCCs but it was not present in any of the normal specimens. It was also expressed in 25% of the leukoplakia specimens, and 90% of the lichen planus samples, but in none of the tissues with hyperplasia only. In some leukoplakia sections, the expression of αv β6 integrin was only seen in a few cells at the tips of the rete ridges, whereas in others a range of basal cells expressed this integrin. Fibronectin and tenascin were both present in the connective tissue underneath the epithelium of all the sections, and their expression was similar in both αv β6 positive and av β6 negative tissues. Based on these findings and earlier results, we speculate that the expression of αvB6 integrin in leukoplakia lesions could play a role in their malignant transformation and particularly in tumour cell migration and invasion in fibronectin-rich matrix. Moreover, in lichen planus lesions, the induction of this integrin may be caused by cytokines associated with inflammation that are specific for lichen. This study proposes that the presence of αv β6 integrin in premalignant tissues could be used as an adjunct in tumour diagnostics.