In the present study, we demonstrate that human and canine cancer cell lines express constitutively activated class I PI3K/Akt/mTORC1 axis signaling, as evidenced by detectable levels of phosphorylated forms of PI3K downstream effectors, including Akt, mTOR, S6RP, 4EBP1 and eIF4E. Here, EIF4EBP1 is linked to cancer.