Inhibition of PI3K pathway by a specific inhibitor LY294002 (20 uM) [33] also resulted in increased p-(Ser51) eIF2α and PKCδ in NB4 cells (Figure 9(b)), indicating that the PI3K/Akt/mTOR pathway is involved in phosphorylation of eIF2α by PKCδ/PKR in APL cells. Here, MTOR is linked to acute promyelocytic leukemia.