Treatment of the pediatric glioblastoma cell line SF188 with the dual pan-Class I PI3K/mTOR inhibitor PI-103 [14]–[16] for 8, 16 and 24 hours at pharmacologically active concentrations corresponding to 5×GI50 (GI50 = 0.2 μM) resulted in an increase in G1 cell population and a decrease in S phase relative to control cells (Figure 1A, Table 1). Here, PIK3CA is linked to glioblastoma.