MTOR and Burkitt lymphoma: Additionally, despite the dismal prognosis for such patients, the rarity of childhood relapsed/refractory BL along with the sheer number of available agents currently under investigation in adults (including numerous agents targeting the PI3K/Akt/mTOR pathway) complicates the choice of which agents to pursue clinically, making the establishment of biological rationale critical to future clinical investigation of novel therapies in pediatric B-NHL.