Mean number of tumors per liver and total liver weights in control and alb-agouti transgenic mice following chemical initiation with DEN. Control, alb-agouti 83, and alb-agouti 86 male mice were each given a single intraperitoneal injection of DEN (10 mg/kg) at 15 days of age. Mice were euthanized at either 36 or 40 weeks after DEN injection and the mean number of tumors per liver (A) and mean total liver weights (B) were determined for each group. Shown are the means ± one standard error of the mean. Sample sizes range from 18–20 for each group. Asterisks indicate significant difference from the controls (p < 0.05).