Localization of glial fibrillary acidic protein in retinal astrocytoma: an immunohistochemical study.

Glial fibrillary acidic protein (GFA) is found in glial filaments, and is specific for reactive or neoplastic astrocytes and ependyma. Using a commercially available antibody to GFA protein, a retinal neoplasm from a patient with neurofibromatosis is intensely stained with the brown immunoperoxidase reaction product. Rather than the less specific phosphotungstic acid hematoxylin (PTAH) or Holzer's stain, antibody to GFAP protein is a relatively rapid, simple, and reliable immunohistochemical technique for formalin-fixed and paraffin-embedded tissue.