TP53 and meningioma: FOXM1 has recently been shown to be a central player in meningioma progression and proliferation by multiple lines of evidence,38,39 and its expression can be promoted by EZH2.40 p21 is a well-known inhibitor of cell cycle progression of which the major positive regulator is p53.41 However, p53 expression was not significantly affected by EPZ-6438, suggesting a p53-independent mechanism of p21 upregulation.