Antileukemic activity of RAPA in AML patients. Blood and marrow blast responses of 4 sensitive patients under RAPA treatment (numbers in upper left of each panel). Marrow response was evaluated at day 28 as described in “Materials and methods.” A Western blot showing the p70S6-kinase (Thr389) and 4E-BP1 (Thr70) phosphorylation status in patient 22 after 10 days of treatment is included. The percentage of blood blasts of this patient at this date was 90% of WBC.