Perifosine increased the sensitivity of high TrkB expressing TB3 tumors to etoposide treatment. A. Mice were treated with vehicle or perifosine at 10mg/kg, 15mg/kg or 20mg/kg for 30 days. The tumor size in treated groups was compared to that of control group. # P<0.05, perifosine (20mg/kg) group vs control group. B. Tumor tissues were stained with P-Akt (Ser473) and P-S6 (Ser235/236) by immunohistochemistry staining. The magnifications of the pictures are 63×. C. Mice were treated with vehicle, perifosine (15mg/kg), etoposide (10mg/kg) or a combination of perifosine (15mg/kg) and etoposide (10mg/kg). The tumor size in treated groups was compared to that of control group. * P<0.05, perifosine (15mg/kg)+etoposide (10mg/kg) group vs control group.