glial fibrillary acidic protein
Also written as: GFAP — glial fibrillary acidic protein
An intermediate filament protein specific to astrocytes, commonly used as an immunohistochemical marker for diagnosing glial tumors.
Full Definition
Glial fibrillary acidic protein (GFAP) is an intermediate filament protein that serves as a structural component of astrocytes and is widely used as a specific immunohistochemical marker in neuropathology. GFAP staining is essential for diagnosing and classifying glial tumors, as it demonstrates astrocytic differentiation in neoplastic cells. The protein is particularly useful in distinguishing astrocytic tumors from other brain tumor types and in identifying reactive astrocytes in various pathological conditions. GFAP expression patterns can vary among different tumor grades and subtypes, with some high-grade gliomas showing focal or reduced GFAP positivity. The marker is also valuable in assessing the glial component of mixed tumors and identifying astrocytic differentiation in poorly differentiated neoplasms.
Usage
Usage note: Acronym GFAP is standard usage; essential marker in glial tumor diagnosis.
In Context
- "Immunohistochemistry revealed strong, diffuse glial fibrillary acidic protein positivity throughout the tumor, confirming astrocytic lineage." — Pathology report
- "The focal loss of glial fibrillary acidic protein expression in areas of the glioblastoma suggested dedifferentiation." — Neuropathology consultation