Integrin expression in middle ear cholesteatoma.

Cholesteatoma is lined by a squamous keratinizing epithelium exhibiting most of the features of normal epidermis. In this study, we investigated by immunohistochemistry the expression of integrin adhesion molecules in primary acquired and recurrent cholesteatomas, and compared it with common epidermal cysts and normal human skin. The results showed that cholesteatoma epithelium exhibited a markedly augmented expression of alpha v integrin subunit and a corresponding increased deposition of vitronectin (alpha v ligand) in the surrounding stroma as compared to epidermal cyst and normal human skin. In contrast, the expression pattern of alpha 2 beta 1, alpha 3 beta 1, and alpha 6 beta 4 integrins as well as the distribution of laminin, collagen IV and fibronectin were similar in cholesteatomas, epidermal cysts and normal human skin. Similar staining pattern was observed in primary acquired and recurrent cholesteatoma.