MAP2K1 and glioblastoma: Importantly, we show that despite elevated Ras/ERK signaling, an ERK-insensitive CIC mutant (ΔEBI) maintains strong repressor function and sensitizes GBM to the effects of selumetinib (AZD6244) a highly selective MEK1/2 inhibitor28,40, which is currently in Phase II and III clinical trials for solid tumors, including pediatric gliomas41.