WIDESPREAD DISTRIBUTION OF TAU IN THE ASTROCYTIC ELEMENTS OF GLIAL TUMORS

Recently tau immunoreactivity has been observed in astrocytes in Alzhe imer's disease and other neurological diseases. We examined the immuno histochemical localization of tau in 110 human brain tumors. Tau was w idely distributed in the glial neoplastic cells and the reactive astro cytes in tumor tissues. In human surgical specimens positive immunosta ining for tau was frequently observed in astrocytic tumors, oligodendr oglial tumors, and glioblastoma, as well as neuronal tumors.The astroc ytic neoplastic cells in medulloblastoma and other poorly differentiat ed tumors were also stained. In contrast, no immunoreactivity was obse rved in meningiomas and schwannomas. The expression of tau in brain tu mors was mainly restricted to those cells with astrocytic features rat her than small immature cells. The expression of tau mRNA was also dem onstrated in astrocytic tumors. In conjunction with the findings of ta u-positive astrocytes in some degenerative disorders, astrocytes are c onsidered to have a potential to express tau through neoplastic transf ormation and reactive processes.