Glial fibrillary acidic protein and cytokeratin in choroid plexus tumors. An immunohistochemical study.

Ten cases of choroid plexus tumors (3 papillomas and 7 carcinomas) were tested for the presence of glial fibrillary acidic protein (GFAP) and cytokeratin. None of the papillomas and one of the carcinomas were positive with GFAP antisera. Cytokeratin-positive cells were present in 2 of 7 carcinomas and in all papillomas. There seems to be a positive correlation between the degree of the tumor differentiation and the expression of intermediate filaments.