Glial Fibrillary Acidic Protein antibody reacts with human GFAP and does not react with other intermediate filaments. Anti-GFAP stains astrocytes, ependymal cells and corresponding tumors. Studies have shown that GFAP may be useful for distinguishing neoplasms of astrocytic origin. GFAP may also be useful in differentiating gliomas from metastatic lesions in the brain. Neuroblastomas, Schwannomas, as well as extra-CNS tumors are not labeled. Negative staining has been observed with lymphatic tissue, muscle, gastrointestinal tract, liver, kidney, pancreas and bladder. Use of a monoclonal antibody typically will increase specificity and eliminate lot-to-lot variation seen with polyclonals.