Combined BC and low dose gemcitabine therapy efficiently suppressed tumor growth and induced tumor cell death in a lung cancer xenograft model. A , A549 cells (2×106) were injected into the flank of 6- to 8-week-old male nude mice to establish a tumor xenograft model. Three weeks later when tumor volumes had reached about 100 mm3, BC or control adenovirus and Tet-off adenovirus (5×106 PFU) were directly injected into tumors, and 10 mg/kg gemcitabine or PBS were administered intraperitoneally. These therapies were performed three times with two days intervals. Tumor volumes were measured every 2 to 3 days for one month. Each experimental group included 5 mice and means ± SDs are plotted. *p < 0.001 and ** p < 0.05 by the Student's t test for differences between tumor volumes between experimental groups. B and C , On day 30 after the last treatment, mice were sacrificed and tumors were extracted. The histogram shows the means ± SDs of tumor weights in each group (n = 5) (B). Tumor sections were analyzed by hematoxylin and eosin staining for histological features, such as, tumor necrosis and apoptosis. Numbers at the top of column indicates magnification (C).