Radioimmunoassay of glioma-associated antigen in cerebrospinal fluid and its usefulness for the diagnosis and monitoring of human glioma.

Quantitative determination of human glioma-associated antigen in cerebrospinal fluids (CSFs) obtained from 66 patients with a variety of neurological diseases was performed by solid-phase radioimmunoassay with a monoclonal antibody (G-22). In this system, the minimum detectable amount of the antigen in the CSF was 8 ng/ml. It was demonstrated that CSF diagnosis of glioblastoma might be possible in the case of small tumors with a diameter of less than 2 cm. CSFs obtained from all 18 patients with glioma were positive and the level varied from 11.2 to 186.1 ng/ml. The antigen level in the cystic fluid of the tumor was higher than that in CSF. There was a tendency for the antigen level in CSF to be correlated with the tumor size and the type of histology. The malignant types of glioblastoma or medulloblastoma showed higher levels than the benign type of ependymoma and astrocytoma. Most types of non-gliomatous brain tumor were negative except immature teratoma, meningioma with central neurofibromatosis, and metastatic brain tumor from lung cancer. We also noted that tumor progression or regression of malignant glioma could be predicted by the monitoring of the antigen in the CSF.