ApcMin/+ mice at 10, 14, or 14 weeks of age received intraperitoneal injection of vehicle or 10 μmol/kg DBZ every other day for 10 days. Two days following the last injection, mice were euthanized to determine the intestinal tumor burden. (A) Comparison of the number of adenomas per mouse in the small intestine between control and DBZ-treated mice in the 3 age group combined. The horizontal bars represent the mean in each group. p < 0.001 by paired two-tailed t test. (B) Comparison of the number of adenomas developed in the small intestine of control and DBZ-treated mice at 12, 16, and 20 weeks. * p < 0.005 and ** p < 0.01 by two-tailed t-test compared to control. (C) The size distribution of adenomas developed in the small intestine at 12, 16 and 20 weeks, respectively, in control and DBZ-treated ApcMin/+ mice. Double-headed arrows indicate significant difference between the two groups (p < 0.01).