MAPK8 and glioblastoma: Immunoblotting of MAPK signaling targets, including BRAF, ERK, p-ERK, P38, p-P38, JNK, and p-JNK in PGC62 and GSC0117 GBM cells with control, doxorubicin, or GDC-0879 treatment after doxorubicin induction further supported this observation (Fig. S11C).