Although MES-like cells from both NF1-mutant and NF1 wild-type glioblastomas showed increased expression of the MEK activation signature, MES-like cells in NF1-mutant glioblastomas showed significantly increased MEK activation compared with MES-like cells in NF1 wild-type tumors (Figure 2F and Supplemental Figure 8C). Here, NF1 is linked to glioblastoma.