Of interest, V-Mos Moloney Murine Sarcoma Viral Oncogene Homolog (MOS), which is responsible for ERK activation as a MAPK kinase kinase (MAPK3K) level in meiosis [54], was upregulated in F3.EGFRviii sphere (Additional file 5: Fig. S4A) as consistent as previous reports the high expression of MOS in ependymal glioma [55] and astrocytic tumors [56]. Here, MAPK1 is linked to astrocytic tumor.