Gross findings and histological appearances of Colon26 tumors after administration of TZT‐1027. TZT‐1027 (2 mg/kg) was administered intravenously to mice bearing Colon26 tumors. (A) Photographs of mice bearing tumors and extirpated tumors are (a) vehicle control and (b) 1 h, (c) 6 h and (d) 24 h after administration of TZT‐1027. (B) After treatment with TZT‐1027, tumor tissues were extirpated, fixed in 10% neutral buffered formalin (pH 7.4), and stained with hematoxylin and eosin. Specimens are (a) vehicle control and (b) 1 h, (c) 3 h and (d) 6 h after administration with TZT‐1027.