Among the genes that are mutated between 5 to 20% in TCGA GBM tumor samples [8, 9], we found mutations in NF1, SPTA1, TCHH and ATRX genes, although, the other genes like PIK3R1, PIK3CA, RB1, IDH1 and KEL were not mutated in any cell line (Figure 3A). This evidence concerns the gene PIK3R1 and glioblastoma.