TP53 and glioblastoma: To explore if miR-203 could up regulate p53 tumor suppressor pathway by inhibiting GAS41 in GBM, we introduced pre- miR-203 in both glioblastoma cell lines used in the study and assessed the expression of GAS41 protein (S3 Fig) as well as the proteins related to p53 pathway by performing western blot analysis using antibodies against GAS 41, p53, phospo-p53 (ser15), p14, p21 and Mdm2.