In vivo antitumor activity of imatinib. (A) Mice injected with 32D cells expressing BCR-ABL were treated with graded doses of intraperitoneal imatinib from days 11 to 18 (○, placebo; ♦, 2.5 mg/kg; ○, 10 mg/kg; ▵, 25 mg/kg; ▪, 60 mg/kg). There was a significant difference in tumor size between controls and mice treated with at least 10 mg/kg. (B) No effect was seen in mice injected with 32D cells expressing v-SRC. Reproduced from Druker et al¹⁸  with permission from Nature, copyright 1996. Error bars indicate mean ± standard deviation.