Metformin repress the growth of AML cells in vivo. (A) Tumor size in OCI-AML3 cells xenografted in nude mice treated with vehicle (black) or metformin (red). Mean of individual tumor sizes are plotted (n = 9 in each group). The P value was determined using the Student t test. (B) Representative photographs of xenografted tumors at day 22. Bars, 10 mm. (C) Kaplan-Meier survival curve of nude mice treated with vehicle (black) or metformin (red) after subcutaneous xenograft with OCI-AML3 cells (n = 9 in each group, 2000-mm³ cut-off). (D) Sections of tumors from mice injected with vehicle or metformin were stained by TUNEL or labeled with phospho-4E-BP1 T^37/46 or Ki-67 antibodies. Representative photos of 3 experiments are shown.