MMP9 and meningioma: The loss of progesterone receptors (PR), which are normally expressed in two thirds of BM, seems to correlate with a higher meningioma grade and the decreased recurrence-free survival time of patients with meningiomas.9–12 Other biochemical factors, like the epithelial membrane antigen, S100, activated caspase 3 and its inhibitor survivin, HER2, metalloproteases MMP-2 and MMP-9 and others have all been proposed as tumour markers significant for the meningioma recurrence.13–19