Rapamycin and CCI-779 effectively inhibit cytokine- or leukemia-triggered mTOR signaling. Quiescent BM-ECs were stimulated for 15 minutes with cytokine media/EGM2 (A-B) or 10% vol/vol leukemia plasma (C-D) and analyzed by Western blot for activation of mTOR downstream substrates (S6K1, S6RibP, 4E-BP1, eIF-4G), and activation of Akt/PKB in the presence of mTOR blockers—rapamycin (A,C) or CCI-779 (B,D). (A) Three BM-EC donors tested. (B) Representative of 4 BM-EC donors tested. (C) Three cases of 5 patients tested. (D) One representative case of 7 patients tested.