KRAS and glioblastoma: One major question, which arises from the data presented in this study, is, if the different effects of the combined treatment with AZD6244 and NVP-BEZ235 in the glioblastoma SNB19 and lung carcinoma A549 cells rely on the different mutational background (SNB19 cells are TP53 and PTEN mutated, whereas A549 cells are KRAS mutated) or on the different tumor entity.