Comparative Western blots of total cell lysates obtained from parental and spheres indicated a higher Btk expression in the GBM spheres generated from both cell lines (Figure 2C); phosphorylated form of Akt and mTOR (p-Akt and p-mTOR respectively) were also up-regulated in the spheres (Figure 2C). This evidence concerns the gene AKT1 and glioblastoma.