PTEN and acute lymphoblastic leukemia: T-ALL patients carry inactivating mutations or deletions of the negative regulator PTEN, PI3K subunits, or AKT1 that lead to aberrant activation of PI3K signaling.84 Specifically, Gu and colleagues111 clearly demonstrated the capability of rapamycin, an mTOR inhibitor, to synergize with dexamethasone in T-ALL cells from pediatric patients.