Expression of periglandular tenascin-C and basement membrane laminin in normal prostate, benign prostatic hyperplasia and prostate carcinoma

To evaluate the structural relationship of the distribution between tenascin (tenascin-C, an extracellular matrix glycoprotein involved in stromal-epithelial interactions in both normal and pathological conditions) and laminin, an important component of the basement membrane, in normal and neoplastic human prostate, and to establish whether changes in the basement membrane are accompanied by changes in tenascin staining. Materials and methods Seventy-five snap-frozen prostate samples representing normal glands, nodular benign prostatic hyperplasia and prostate carcinoma were stained for tenascin. From these, 15 samples were selected for dual-immunofluorescence staining and a confocal laser scan microscope was used to simultaneously visualize tenascin and laminin immunoreactivity. Results Tenascin was expressed in the extracellular matrix, mainly at the periphery of the glands, in turnour loci and blood vessels. In cases with intact basement membranes, e.g. normal glands and hyperplastic lesions, tenascin expression was weak. Low- and moderate-grade tumours were characterized by strong tenascin expression, while laminin expression was weak and/or showed discontinuities, indicating disturbances in basement membrane composition. Highgrade tumours had sparse tenascin staining and a marked loss of laminin immunoreactivity. Conclusion These results indicate that periglandular tenascin expression correlates with the integrity of the basement membrane in the human prostate. By influencing stromal-epithelial interactions, tenascin may play a role in maintaining tissue homeostasis in the prostate.