As it concerns meningiomas, the staining revealed: (a) mainly cytoplasmic MMP-9 reactivity and a strong signal in atypical meningiomas compared with low-grade ones (p = 0.036) (Fig. 1, panel d, and Table 2); (b) Ki-67 index was more expressed in grade II meningioma compared with grade I specimens (p < 0.001), whereas progesterone receptor (PR) did not correlated with the tumor grading (p = 0.257). This evidence concerns the gene MMP9 and meningioma.