Proliferative activity of central neurocytoma: Measurement of tumor volume doubling time,MIB-1 staining index and bromodeoxyuridine labeling index

Central neurocytoma is considered to be a benign intracranial neoplasm, but little is known about the biological behavior of this type of tumor.Proliferative activity of central neurocytoma was measured in 10 cases using MIB-1 staining for Ki-67 antigen.The MIB-1 staining value varied from < 0.1% to 5.6%, to indicating that some of these tumors have proliferative potential similar to that of anaplastic astrocytoma or malignant meningioma. Thebromodeoxyuridine labeling index (BUdR LI, BrdU LI) was measured in 2 cases and the results correlated well with those of the MIB-1 analysis. Tumor volume doubling time (Td) measured in one case was 358 days which is similar to that of malignant meningioma.In one case, the MIB-1 value taken beforeand after 58 Gy of radiation treatment decreased markedly from 5.6%to 0.2%. The other 9 cases were also treated by radiation therapy (50—60 Gy) and no tumor recurrence was observed during follow-up periods ranging from 23 to 160 months. Another two patients with partially removed and 3 with subtotallyremoved tumors showing relatively high MIB-1 values might also have benefited from radiation therapy.