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

BACKGROUND: 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.

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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.