Despite some heterogeneity, all the B-pre ALL cell lines displayed phosphorylation at the Ser 2448 and Ser 2481 (readout for mTORC1 and mTORC2, respectively) residues of mTOR and at the Ser 473 residue of Akt, which are indicative of the constitutive activation of this signaling pathway (Fig. 1). Here, MTOR is linked to acute lymphoblastic leukemia.