Routine pathologic examination cannot distinctively predict the clinical course of meningiomas because even histologically benign tumors may recur after gross total resection. Therefore, numerous efforts have been made to evaluate the meningioma growth fraction and its prognostic value. However, a universally applicable proliferative marker for meningioma outcome is not yet a reality.
To investigate the prognostic utility of 3 proliferative markers, namely, Ki-67, DNA topoisomerase II-alpha (topoII), and cyclin A in a representative series of intracranial meningiomas.
Two hundred sixty-three adult patients with intracranial meningiomas (208 benign, 42 atypical, and 13 anaplastic) were studied retrospectively. Tumor specimens were immunohistochemically examined with antibodies to Ki-67 (MM-1), topoII, and cyclin A. A computerized color image analyzer was used to count immunostained nuclei.
The topoII and cyclin A scores exhibited a close correlation with Ki-67 immunostaining. Significant differences between the indices for all 3 markers were noted among the 3 grades of meningiomas. The scores for all 3 markers were significantly different between recurrent and nonrecurrent meningiomas, including benign tumors that were treated with gross total resection. Recurrence-free survival was significantly reduced for cases with a Ki-67 labeling index (LI) of 4.4% or greater, a topoII LI of 3.2% or greater, and a cyclin A LI of 3.1% or greater. Multivariate analysis revealed that the risk of recurrence for the entire meningioma cohort was significantly associated with tumor grade (hazard ratio = 2.7; P =.004), topoII LI of 3.2% or greater (hazard ratio = 5.5; P <.001), and a cyclin A LI of 3.1% or greater (hazard ratio = 2.4; P =.01).
There is a close correlation in the expression of these 3 proliferative markers in meningiomas, and all of the markers showed a significant association with tumor grade, recurrence rate, and recurrence-free survival. Consequently, in addition to Ki-67, immunoexpression of topoII and cyclin A is available for predicting meningioma recurrence. Moreover, the topoII and cyclin A staining scores were found to be more sensitive predictors for meningioma progression than Ki-67 and, therefore, either of these 2 markers may prove to be clinically informative and useful.