Culture of four primary cases of WHO grade 1 meningiomas showed that BMP-4 promotes meningioma growth in an autocrine/paracrine pathway via Smad1 [9], and BMP-4 is highly expressed in osteolytic meningiomas [22], but BMP signaling inhibitors or their inhibitors are not known to be involved in cellular senescence or formation of psammoma bodies. Here, SMAD1 is linked to meningioma.