Integrin expression in squamous neoplasia of the cervix.

Epithelial cell-basement membrane interactions are important in maintaining tissue architecture and function, and the anatomical and functional relationships between epithelial cells and their basement membranes are clearly altered in malignancy. These interactions are thought to be largely mediated by the integrins, a family of heterodimeric transmembrane glycoproteins, each consisting of an α and a β chain. Epithelial integrins mainly belong to the β1 (VLA) subfamily, which forms receptors for matrix macromolecules such as fibronectin, laminin, and collagen. There is evidence that integrin expression changes in some epithelial malignancies, possibly in relation to invasive potential. Integrin expression in cervical neoplasia was studied by immunohistochemical examination of prospectively collected colposcopic biopsies. Well-characterized monoclonal antibodies against β1–4, αl–6, and αV integrins were used to examine normal, koilocytic, and dysplastic cervical squamous epithelium, and invasive squamous carcinoma. β1, β4, α2, α3, α6, and αV were expressed by the basal layer of normal cervical squamous epithelium and by dysplastic cells in CIN (cervical intraepithelial neoplasia) 1 and 2, with none being lost and no new chains acquired. In CIN3, these integrins were either expressed throughout the ectocervical epithelium or restricted to the basal layer. In the latter cases, integrin expression was retained to a greater degree by dysplastic squamous epithelium within endocervical glands. These patterns could not be correlated with age or smear history in the cases examined. Patterns of integrin expression in neoplastic cervical epithelium therefore differ from those of normal cervical epithelium. It is possible that these changes may be related to changes in cellular function occurring during neoplastic progression.