AP23994 inhibited TC71 tumor growth in vivo. A, TC71 cells were inoculated into nude mice. Starting on day 3, mice were treated orally with AP23994, PBS, or vehicle alone daily for 3 wk. Tumor size was measured and the average tumor volume was calculated in each group. *, P < 0.01, compared with control or vehicle-treated tumors. B, apoptosis and proliferation of excised tumors were analyzed using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling or Ki-67 staining, respectively. C, Ki-67-positive cells were quantified under high-power field. Mean ± SD of five randomized fields from different samples in each group. *, P < 0.05. D, total protein was extracted from the tumors of each group. Lyn inactivation was determined by Western blot using anti-Lyn (Tyr507) antibody.