[Importance of immunohistochemistry for neuro-oncology. III. Demonstration of glial fibrillary acidic proteins (GFAP) in anaplastic astrocytomas and glioblastomas].

Expression of gliofibrillary acidic protein in 23 anaplastic astrocytomas and 33 glioblastomas has been investigated and correlated with tumor behavior as reflected in both the length of the preoperative history and in the post-operative survival time. Three degrees of positive immunoreactivity to anti-GFAP can be distinguished: positive GFAP reaction in more than 2/3 of cells; in 1/3 to 2/3 of all cells; in less than 1/3 of all cells; negative reaction. All anaplastic astrocytomas and 27 of 33 glioblastomas showed GFAP positive reactions. The proportion of highly reactive tumors is higher by anaplastic astrocytomas than by glioblastomas (7 of 33). For both astrocytomas and glioblastomas there is a tendency for a decrease in the expression of GFAP to be associated with a shorter preoperative history and with a shorter survival time. This is more prominent for astrocytomas than for glioblastomas. This finding supports the opinion expressed in previous publications that the GFAP expression is reversely related to the level of tumor anaplasticity.