NTRK2 and acute lymphoblastic leukemia: Upon short-term treatments of Ba/F3 ShPTEN-NTRK2-Tel as well as T-ALL cell lines with PI3K isoform-selective inhibitors, we found that BYL719 [18] (a p110α-selective inhibitor) greatly reduced AKT but not S6 phosphorylation, whereas GS-1101 [19] (idelalisib, a p110δ-selective inhibitor) inhibited S6 protein phosphorylation or AKT phosphorylation depending on cell lines (Figure 4a and b).