Immunohistochemical properties of human optic nerve glioma: Evidence of type 1 astrocyte origin

The peroxidase-antiperoxidase method was used to study ten surgically obtained human optic nerve gliomas (pilocytic astrocytomas). All tissues were formalin fixed and paraffin embedded. Primary antisera included glial fibrillary acidic protein (GFAP), HNK-1 (type 1 astrocyte precursor marker), A2B5 (type 2 astrocyte precursor marker), S-100, vimentin, myelin basic protein (MBP), laminin, keratin, cytokeratin, epithelial membrane antigen (EMA), and neuron-specific enolase (NSE). Neoplastic astrocytes in optic nerve gliomas stained with GFAP, HNK-1, S-100, and vimentin. Oligodendrocytes and myelin sheaths stained for MBP, and NSE stained surviving axons in the tumors. Neoplastic astrocytes did not stain for A2B5, keratin, cytokeratin, EMA, or laminin. These results suggest that human optic nerve gliomas (pilocytic astrocytomas) arise from type 1 astrocytes.