As the kinetics of the expression of MDM4, p53, and p53 target gene products after the CEP-1347 treatment have not yet been examined in brain tumor cell lines (i.e., glioma and meningioma cell lines), we conducted a time course analysis of their expression in wild-type p53-expressing glioblastoma (A172) and meningioma (IOMM-Lee) cell lines. This evidence concerns the gene TP53 and meningioma.