Expression of the extracellular matrix protein tenascin in laryngeal epithelial lesions: correlation with fibronectin, CD44 cathepsin D and proliferation indices

Tenascin (TN) is an extracellular matrix glycoprotein expressed in areas of epithelial-mesenchymal interactions during embryogenesis and in neoplasia. We studied the expression of TN in a series of 35 squamous cell invasive c arcinomas of the larynx, 13 in situ carcinomas, 41 cases of dysplasia, 10 p apillomas and 18 cases of keratosis using the monoclonal antibody TN2 on pa raffin-embedded tissue. TN expression was correlated with the expression of fibronectin, CD44 and cathepsin D (CD) proteins, with the proliferation in dices Ki-67 and proliferating cell nuclear antigen (PCNA) as well as with c onventional clinicopathological variables. Malignant tumours showed a signi ficantly greater stromal TN staining than benign lesions. In invasive carci nomas, the immunoreactivity was statistically higher than that in situ (P=0 .01), dysplastic lesions (P<0.0001), papillomas (P=0.004) and keratosis (P< 0.0001). A statistically significant difference of TN expression between in situ and dysplastic lesions was observed (P=0.001). Tn invasive lesions, T N expression was statistically correlated with CD44 expression (P=0.02) and a trend for correlation with CD of tumour cells and fibronectin expression was found (P=0.06 and P=0.09, respectively). The relationship of TN expres sion with the histological grade and the proliferative activity was insigni ficant. In conclusion, stromal TN expression may be involved in the complex mechanism of development of laryngeal lesions and may help to predict the risk of progression of pre-cancerous lesions to cancer.