“…However, the optimal management approach for postoperative radiation treatment, especially for WHO Grade I meningiomas, remains to be elucidated. 32,38 The Simpson grading system alone appears to be inconclusive with respect to this issue because the immediate necessity of radiation therapy for benign meningiomas after Simpson Grade I, II, or III resection is usually minimal. Several studies have advocated the use of proliferation markers such as the MIB-1 LI for anticipating tumor recurrence based on follow-up data from a relatively small number of patients, 3,4,13,14,23,26,40 whereas other studies have reported the limitations of such markers.…”