CLINICAL AND HISTOPATHOLOGICAL ANALYSIS OF PROLIFERATIVE POTENTIALS OF RECURRENT AND NONRECURRENT MENINGIOMAS

Proliferative potentials of meningiomas from 127 patients were examine d immunohistochemically using the anti-Ki-67 monoclonal antibody, MIB- 1, on paraffin sections, and the correlation among MIB-1 staining inde x (SI), histopathological finding, and clinial course of the disease w as analyzed retrospectively. The mean MIB-1 SI of 50 male patients wit h meningioma was 5.5%, whereas that of 77 female patients was 2.7%. Hi gher MIB-1 SI were observed for younger patients. These age- and sex-r elated differences in MIB-1 SI were statistically significant. The pat ients were assigned to one of three groups: those with non-recurrent m eningioma (n = 73); those with recurrent meningioma in whom the specim ens obtained during the initial surgery were used to calculate the MIB -1 SI (ii = 21); and those with recurrent meningioma for whom the spec imens obtained during the surgery for recurrent tumors were used to ca lculate the MIB-1 SI(I? = 33). The mean MIB-1 SI in these patients wer e 1.6%, 3.6%, and 8.8%, respectively, and there were statistically sig nificant differences among these three groups. Statistical analyses re veal that meningiomas with a MIB-1 SI of 3% or more have a significant ly high tendency for recurrence during the clinical courses, especiall y within the first 10-year follow-up periods. Moreover, there is stati stically significant correlation between MIB-1 SI and recurrence in ea ch Simpson's grade. The time interval to the next recurrence for recur rent meningiomas is associated with the proliferative potential repres ented by the MIB-1 SI, and a correlation equation has been proposed to predict the date of the next recurrence. Analyses on cellularity of m eningiomas revealed no statistically significant difference in cellula rity between nonrecurrent and recurrent meningiomas. There was no stat istically significant relationship between cellularity and MIB-1 SI of meningiomas. In conclusion, examination on proliferative potentials o f meningiomas using MIB-1 SI is very important for biological and hist opathologicl analyses and the prediction of future recurrence.