In addition, IHC analysis of brain sections of GL-261 and SB mouse GBM cell-derived intracranial tumor-bearing mice demonstrated that GDC-0879 treatment significantly reduced the staining intensities of the MAPK signaling targets, including BRAF, ERK, p-ERK, P38, p-P38, JNK, and p-JNK (Fig. S19A, B), supporting the potential role of GDC-0879 functioning through MAPK pathway, while targeting SASP in GBM. Here, MAPK8 is linked to glioblastoma.