Neuron-specific gamma-enolase derived from human glioma.

Neuron-specific gamma-enolase in human neurogenic tumors, including gliomas, transplanted gliomas, and permanent human glioma cell lines, was studied quantitatively, using newly established enzyme immunoassay methods, together with immunostaining of the tissue and cell preparations. A significantly high level of gamma-enolase was found in some glioblastomas, astrocytomas and oligodendrogliomas as well as medulloblastomas. Glioblastomas transplanted into mice and cultured cell lines derived from the same origins, as well as the permanent human glioma cell lines, also contained gamma-enolase, although the contents were low compared with findings in the original tumor tissues. Immunohistochemically, gamma-enolase stained intensely in the glioblastomatous cells. Serum gamma-enolase concentrations in some patients with gliomas and those of all the transplanted mice were enhanced. The serum gamma-enolase levels in the mice correlated well with size of the transplanted tumor tissues. These results indicate that neuron-specific gamma-enolase is produced in some neurogenic tumors of nonneuronal origin, therefore, serum gamma-enolase may be a useful biomarker for monitoring the extent of disease in patients with gliomas.