DIFFERENTIAL EXPRESSION OF EXTRACELLULAR-MATRIX MOLECULES AND THE ALPHA(6)-INTEGRINS IN THE NORMAL AND NEOPLASTIC PROSTATE

The epithelial basal lamina composition and integrin expression profil e of normal and neoplastic human prostate was characterized using immu nohistochemical analysis of frozen samples. The major components of th e basal lamina surrounding normal acini were laminin, type IV collagen , entactin, and type VII collagen with variable amounts of tenascin. T he basal lamina of neoplastic acini had a similar composition, except for the loss of type VII collagen, which was observed in all grades of carcinoma. The basal cells of the normal prostate express the alpha(6 )-, beta(1)-, and beta(4)-integrin subunits, suggesting that both the alpha(6) beta(1)- and alpha(6) beta(4)-integrin complexes are formed. In prostate carcinoma there is a complete loss of beta(4) expression a nd the alpha(6)- and beta(1)-integrin subunits, which are restricted t o the basal and basal lateral surfaces of basal cells, ae distributed diffusely throughout the cytoplasmic membrane. The differential expres sion of type VII collagen and beta(4) are discussed in relationship to their possible role in tumor progression.