Some immunohistochemical techniques currently available to assist in diagnostic problems in tumours of the central nervous system
| Antibody | Molecular specificity | Diagnostic use |
|---|---|---|
| ACTH, adrenocorticotrophin; FSH, follicle stimulating hormone; LH, luteinising hormone; TSH, thyroid stimulating hormone. | ||
| Gliofibrillary acidic protein (GFAP) | An intermediate filament protein of 52 kDa | Astrocytomas and ependymomas |
| S-100 protein | A family of proteins found in neuroectodermal tissues | Cells of neural crest origin and their neoplasms (gliomas, nerve sheath and choroid plexus tumours, melanomas, and granular cell myoblastomas) |
| Synaptophysin | A membrane glycoprotein. Occurs in presynaptic vesicles of neurones, adrenal medulla, and neuromuscular junctions | Tumours showing neurosecretory differentiation such as neuroblastoma, neurocytoma, medulloblastoma, paraganglioma, pituitary neoplasms, and a wide variety of neuroendocrine tumours |
| Chromogranin | An acidic protein widely distributed in neuronal tissues and in the secretory granules of endocrine cells | Neuroendocrine cells and their neoplasms |
| Protein gene product 9.5 | A member of the ubiquitin C terminal hydroxylase family of proteins found in neurones and nerve fibres, in neuroendocrine cells, and in some non-neural cells | May be useful as a marker of neurones and the ubiquinated inclusions found in several neurodegenerative diseases |
| Neurone specific enolase | Reacts with the gamma-gamma isoenzyme found in neurones, neuroendocrine cells, and a variety of non-neuronal cell types | Neuroendocrine cells and a wide variety of tumours of the nervous system (gliomas, meningiomas, ependymomas, choroid plexus papillomas, schwannomas, medulloblastomas, and some carcinomas (breast and lung)) |
| Neurofilament antibodies | Several antibodies are available that react with the 68 kDa, 160 kDa, and 200 kDa components of neurofilaments | Tumours of neural lineage including ganglioneuromas, paragangliomas, neuroblastomas, medulloblastomas, and gangliogliomas |
| Epithelial membrane antigen | Found in the epithelial membrane of a variety of normal tissues | Identification of tumours of epithelial origin, chordomas, meningiomas, and choroid plexus neoplasms |
| Cytokeratins | There are numerous antigens expressed by different epithelia and mixtures of antibodies are available | Epithelial tumours, craniopharyngiomas, meningiomas, choroid plexus neoplasms, chordomas, and some germ cell tumours |
| Pituitary hormones | Prolactin, growth hormone, ACTH, FSH, LH, and TSH | Neoplasms of the pituitary gland |
| Embryonal cell markers: placental alkaline phosphatase, human chorionic gonadotrophin, α fetoprotein | The first two proteins are found in placenta and α fetoprotein is found in a variety of fetal tissues but not usually in the adult | Germ cell neoplasms |
| Vimentin | An intermediate filament protein of 57 kDa found mainly in cells of mesenchymal origin | Meningiomas, and nerve sheath tumours. Of limited use because it stains a very wide variety of cell types |
| S-antigen | This antigen is found in photoreceptors and pinealocytes. It is a cytosolic protein that regulates phototransduction in retinal rods. Its function in the pineal is unknown | Retinoblastomas and sometimes present in tumours of the pineal gland, and medulloblastoma |
| Peripherin | A 57 kDa intermediate filament found in the developing peripheral nervous system and also enriched in neuronal derivatives of the neural crest | Peripheral neurones including enteric ganglion cells. Also expressed in neuroblastomas and ganglioneuroblastomas but does not stain chromaffin cells |
| Ki67 | The antigen is within the nucleolus during late G1, S, G2, and M phases of cell proliferation | There is a reasonable correlation with the grade of neoplasm but needs to be interpreted with caution. The Ki67 index does not always correlate with recurrence rate |