Expression of tenascin-C in astrocytic tumors: Its relevance to proliferation and angiogenesis

BACKGROUND The expression and distribution of the extracellular matrix protein tenasci n-C (TN-C) may be enhanced in human astrocytomas, The purpose of this study is to evaluate the expression of TN-C according to histological malignancy of tumor cells and its relevance to neoplastic angiogenesis in human astro cytic tumors. METHODS Between 1994 and 1998, 52 astrocytic tumor specimens including 4 pilocytic astrocytomas, 13 astrocytomas, 3 anaplastic astrocytomas, and 32 glioblasto mas were used in this study. A retrospective analysis was performed to eval uate a statistical correlation between TN-C expression and proliferative in dices. We characterized the expression of TN-C in neoplastic vessels, aroun d individual tumor cells as a tumor network, and in tumor cells by immunohi stochemistry using antibodies against human TN-C. The proliferative indices were also investigated by immunostaining with the MIB-1 antibody against t he Ki-67 proliferation antigen. RESULTS TN-C immunoreactivity was found to be enhanced in tumor vessels and tumor n etworks of high-grade astrocytic tumors. The vascular TN-C deposition was g reater in high-grade than in low-grade astrocytic tumors (p < 0.05). Its ex pression was the most intense in glioblastomas. Proliferation indices incre ased with tumor grade and MIB-1 labeling index (LI) was highest in glioblas tomas. Moreover, expression of TN-C in tumor vessels was correlated with pr oliferative indices. CONCLUSIONS Our data show that TN-C in human astrocytic tumors may be identified as a f actor contributing to malignant progression. And also, enhanced expression of TN-C in tumor vessels having a high proliferative index indicates that T N-C could be involved in neoplastic angiogensis. (C) 2000 by Elsevier Scien ce Inc.