AKT1 and diffuse large B-cell lymphoma: These results are consistent with our previous reports showing that roflumilast, a phosphodiesterase 4 inhibitor approved by the US Food and Drug Administration, downregulates MYC expression by suppressing AKT/mTOR signaling in DLBCL cells [18], suggesting that the AKT/mTOR pathway is important in the regulation of MYC expression.