Glial Fibrillary Acidic Protein (GFAP) is specific to astrocytes (i.e., glial cells) and ependymal cells of the central nervous system. MAb to GFAP is useful in differentiating primary gliomas from metastatic lesions in the brain and for documenting astrocytic differentiation in tumors outside the CNS. GFAP stains astrocytes, glial cells, ependymal cells, and their corresponding tumors. Many types of neural tumors such as neuroblastomas, Schwannomas, as well as extra-CNS tumors are not labeled. GA-5 is very sensitive in detecting GFAP in routine formalin-fixed, paraffin-embedded tissues.