EXPRESSION OF PERIGLANDULAR TENASCIN-C AND BASEMENT-MEMBRANE LAMININ IN NORMAL PROSTATE, BENIGN PROSTATIC HYPERPLASIA AND PROSTATE CARCINOMA

Objective To evaluate the structural relationship of the distribution between tenascin (tenascin-C, an extracellular matrix glycoprotein inv olved in stromal-epithelial interactions in both normal and pathologic al conditions) and laminin, an important component of the basement mem brane, in normal and neoplastic human prostate, and to establish wheth er changes in the basement membrane are accompanied by changes in tena scin staining. Materials and methods Seventy-five snap-frozen prostate samples representing normal glands, nodular benign prostatic hyperpla sia and prostate carcinoma were stained for tenascin. From these, 15 s amples were selected for dual-immunofluorescence staining and a confoc al laser scan microscope was used to simultaneously visualize tenascin and laminin immunoreactivity. Results Tenascin was expressed in the e xtracellular matrix, mainly at the periphery of the glands, in tumour foci 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 discontinu ities, indicating disturbances in basement membrane composition. High- grade tumours had sparse tenascin staining and a marked loss of lamini n immunoreactivity. Conclusion These results indicate that periglandul ar tenascin expression correlates with the integrity of the basement m embrane in the human prostate. By influencing stromal-epithelial inter actions, tenascin may play a role in maintaining tissue homeostasis in the prostate.