SMAD4 and meningioma: We performed immunohistochemistry for detection of FRAT1 and SMAD4 protein levels in FFPE samples of 35 patients of our previous study [13], including 20 WHO grade I, 10 WHO grade II and 5 WHO grade III meningiomas, and correlated Immuno-Reactive-Score (IRS) with Ki-67 labeling index as measure of cell proliferation.