In vivo antitumor effect of dasatinib on P815 mastocytoma. DBA/2 mice were subcutaneously inoculated with 2 × 10⁶ P815 tumor cells on day 0. Tumor-bearing mice were treated with vehicle or dasatinib (150 mg/kg) on day 8, 9, and 10 by gavage. For depletion experiment, mice were injected IP with 200 μg of rat IgG or CD8 depletion antibodies starting from day 8 once a week. (A) Tumor sizes of mice treated with vehicle or dasatinib (*P = .0354). (B) Kaplan-Meier survival curve of the tumor-bearing mice for 2 different groups (*P = .0447). (C) Representative H&E-stained slides of control tumor and dasatinib-treated tumor. (D) Tumor sizes of CD4⁺/CD8⁺ T-cell depletion experiment (vehicle + IgG vs dasatinib + IgG: *P = .0427). (E) Kaplan-Meier survival curve of CD4⁺/CD8⁺ T-cell depletion experiment (vehicle + IgG vs dasatinib + IgG: *P = .0503).