Actinomycin-D treatment of the adult glioblastoma cell line U373 as well as of the paediatric medulloblastoma cell lines DAOY and UW228-3, all known to harbour an inactivating TP53 mutation, showed either no effect (U373) or an inhibition of cell viability only at much higher concentrations similar to that of the embryonic stem cells (DAOY: 3 nM; UW228-3: 3 nM) (Supplementary Figure S4). This evidence concerns the gene TP53 and glioblastoma.