Abstract
Glial fibrillary acidic protein (GFA) was assayed in nerve-tumour extracts and located in these tumours by indirect immunofluorescence study. We conclude that GFA is a specific marker of both malignant and normal astrocytes. Non-astrocytic tumours (oligodendroglioma, meningioma) do not contain GFA. Tumours with astrocytic differentiation potential (medulloblastoma) may contain GFA. Comparison of microscopic and GFA assays leads us to conclude that GFA concentration is proportional to the amount of malignant astrocytes in the tumour and inversely proportional to the necrotic area of a tumour. Normal tissue GFA and glioblastoma GFA were found to be immunologically identical.