Other signaling pathways shown to be activated in meningiomas are the phospholipase A2–arachidonic acid–cyclooxygenase pathway [51], the phospholipase C γ1 (PLCγ1)–protein kinase C pathway (PKC) [52], and the transforming growth factor-β (TGFβ)–SMAD signaling pathway [53,54], which act as inhibitory mechanisms of meningioma growth, thus representing potential targets of treatment. This evidence concerns the gene TGFB1 and meningioma.