MYELIN BASIC-PROTEIN IN THE CEREBROSPINAL-FLUID OF PATIENTS WITH BRAIN-TUMORS

WE MEASURED THE level of myelin basic protein (MBP) in the cerebrospinal fluid (CSF) of patients with various kinds of tumors, including malignant tumors, using radioimmunoassay. The CSF had been obtained by lumbar puncture through an Ommaya reservoir or a shunt device placed in the lateral ventricle. The level of MBP was high (> 4 ng/ml) in the patients with meningeal dissemination of malignant tumors, but in those who showed a good response to chemotherapy and/or radiation, it decreased or returned to the normal level, with improvement on the computed tomography and magnetic resonance imaging, cytological, general CSF, and neurological findings. Of seven malignant gliomas without CSF dissemination, six showed an elevated level of MBP before selective intra-arterial chemotherapy with a combination of etoposide and cisplatin administered via a microcatheter placed at A1, M1, P1-P2, and the basilar top. All CSF specimens obtained during the period of the intra-arterial chemotherapy showed an abnormally high (> 4 ng/ml) level of MBP that exceeded the prechemotherapy level. The MBP level decreased or returned to normal in the patients with a good response to chemotherapy after intra-arterial chemotherapy. In some patients with multiple metastatic brain tumors, the MBP level was elevated before treatment and returned to normal after treatment (surgical removal, chemotherapy, and/or irradiation) in all except one. Thus, there was a clear correlation between the timing of treatment and changes in imaging studies and MBP levels. Only 3 of the 18 patients who had received irradiation and demonstrated no brain tumors on magnetic resonance imaging after radiation therapy showed an abnormal MBP level; one developed brain atrophy 1 month after chemotherapy and radiation therapy for multiple metastatic brain tumor, one had massive edema after the macroscopically total removal of a recurrent anaplastic meningioma, and the other had necrotizing encephalopathy, which developed 6 months after the complete disappearance of anaplastic astrocytoma by chemotherapy and radiation therapy. Patients with benign brain tumors generally showed a normal MBP level; only 2 of 22 patients, one with meningioma with very extensive edema and the other with an unstable postoperative condition after the total removal of a large craniopharyngioma, showed a high MBP level. These findings suggest that the MBP level reflects not only brain damage in the acute stage but also the effect of treatment, including surgery, radiation, and/or chemotherapy, in malignant brain tumors.