The application of flow cytometry for evaluating biological aggressiveness of intracranial meningiomas

Meningiomas have classically been considered to include benign and atypical/anaplastic tumors. Despite the availability of clinical and pathologic parameters for prognostic prediction prognosis, the behavior of each meningioma may be difficult to predict. Here, we used DNA flow-cytometric studies to predict biological tumor behaviors of intracranial meningiomas.

The specimens were obtained from fresh tumoral tissues of 43 microsurgically resected meningiomas as approved by the institutional review board. The presence of G2/M-phase and S+G2/M-phase fractions were analyzed and correlated with the proliferation index of Ki-67 and the World Health Organization grading. The check point of G2/M-phase fraction, cyclin B, and pCdk1 (Y15), were analyzed by Western blotting.

Our results showed that there were significant differences in Ki-67, G2/M-phase, S+G2/M-phase fractions, and cyclin B between benign and atypical/anaplastic meningiomas. The optimal cutoff point of G2/M-phase and S+G2/M-phase fractions were 5.12 and 7.52%, respectively, and this can be used to discriminate those cases with benign or atypical/anaplastic meningiomas. Besides, both the G2/M-phase and S+G2/M-phase fractions were correlated well with Ki-67 and the histopathological features such as focal necrosis, infiltration of dura mater and mitotic activity. In addition, the occurrence of tumor recurrence and patient age were correlated to the G2/M-phase and S+G2/M-phase fractions, respectively. The G2/M-phase and S+G2/M-phase fractions, however, did not correlate well with histologic invasion to adjacent bone, sinus, or brain tissues.

The use of flow cytometry facilitates additional information for G2/M-phase and S+G2/M-phase fractions represent tumoral grading and risk of recurrence in patients with meningiomas.