The role of glial fibrillary acidic protein in the diagnosis of central nervous system tumors.

Eighty glial and non-glial brain tumors have been studied to date using an immunologically specific and highly sensitive method of staining GFA protein which is applicable to formalin fixed and paraffin embedded tissue. Eight of these cases have been described and illustrated in some detail. GFA protein was present in all astrocytes and astrocytomas studied and in a proportion of ependymal cells and ependymomas. Some tumor cells have been demonstrated by this method to be glial despite the complete lack of blue fibrillar staining with PTAH and the absence of all morphological similarity to glial cells. In such cases the demonstration of GFA protein by this method has been valuable in establishing a diagnosis. In addition to its diagnostic value in specific cases, the method promises to shed light on unsolved problems of tumor cytogenesis.