DISTRIBUTION PATTERN OF TENASCIN-C IN NORMAL AND NEOPLASTIC MESENCHYMAL TISSUES

Descriptions for tenascin-C distribution are largely restricted to epi thelial tumours, The present study utilized newly developed and charac terized monoclonal (hT191) and polyclonal antibodies to investigate th e distribution pattern of tenascin-C in a panel of mesenchymal tumours , which was contrasted with normal tissue. The specific antibodies rec ognized the distinctive star-like hexabrachion protein isolated from t ransformed cell-culture medium and serum from normal individuals, In n ormal tissues, a strong tenascin-C expression in the extracellular mat rix was largely restricted to basement-membrane regions of epithelium and tonsilar sinusoids, pericellularly within smooth-muscle bundles, a ssociated with perimysial, -chondrial, -neurial and -tendon surfaces, and diffusely within vascular adventitia, it was found in the correspo nding tumours of the neural sheath (schwannoma) and smooth muscle (lei omyosarcoma), and was abundantly present around certain blood vessels of mesenchymal tumours. Although not detected in normal muscle, or in adipose or fibrous connective tissue, neo-expression of tenascin-C was shown in more than half of the rhabdomyosarcomas, fibromas and liposa rcomas, with an increased positive percentage in variably malignant my xoid liposarcomas compared with lipoma-like sarcomas, Tenascin-C was t ypically found in the extracellular matrix of soft-tissue tumours, but was notably absent from the epithelial-cell components of mixed epith elial/mesenchymal tumours, Its apparently enhanced expression in soft- tissue tumours differs from that of most other large extracellular-mat rix proteins, suggesting possible functional involvement of the cell-a dhesion molecule, tenascin-C, in the neoplastic phenotype. (C) 1997 Wi ley-Liss, Inc.