MTOR and B-cell non-Hodgkin lymphoma: Since a direct inhibitor targeting the eIF4E level is currently not available, several studies have aimed at targeting eIF4E using indirect approaches.[27, 28] An important upstream regulator of the eIF4E pathway is mTOR, a serine/threonine protein kinase that functions by phosphorylating eIF4E binding proteins (4E-BPs).[29] The mTOR pathway has been shown to be constitutively activated in a high percentage of B-cell lymphomas, [11, 30, 31] however, some lymphomas develop resistance to mTORC1 inhibition.