Clinical significance of tenascin-C expression in osteosarcoma: tenascin-C promotes distant metastases of osteosarcoma. Tenascin-C (TN-C) is one of extracellular matrix glycoproteins. We have immunohistochemically examined the TN-C expression of 33 primary osteosarcoma paraffin-embedded samples. The TN-C expression of the patient group with metastases was higher than that of the group without metastases at significant difference, and the survival curves show a tendency for poor outcome in the high grade staining group. Moreover, the supplemental TN-C had an effect of easier migration of a human osteosarcoma cell line (HOS) in vitro. The results may suggest that TN-C help osteosarcoma cells to migrate and to metastasize.