[Expression of glial fibrillary acidic protein and protein S-100 in cerebral astrocytic gliomas of varying degrees of malignancy (immunohistochemical study)].

Expression of the glial fibrillary acidic protein (GFAP) and S-100 protein was examined in 76 astrocytic gliomas (AG) with different degree of malignancy, which were subdivided into 4 groups: pilocytic astrocytoma, mixed astrocytoma, anaplastic astrocytoma and glioblastoma. Combined light-microscopical and immunohistochemical investigation detected several variants among different kinds of malignant AG that were distinguished by cytological composition and immunomorphology. Gemistocytic and polymorphic nuclear types were distinguished among anaplastic astrocytoma. Glioblastomas were subdivided into multiforme, isomorphic and gemistocytic variants. It was established that fractions of GFAP-negative cells occur in benign and malignant AG. Thus, the presence of population of immunonegative cells in AG is not a sign of high-grade tumor anaplasia. Groups of GFAP-positive cells around tumor vessels were found in malignant AG only.