Fig. 1.

Cecal tumor development in AhR^−/− mice. (A) Representative profiles of colon tumors at the cecum in AhR^−/− mice. (B) Relationship between the time course of macroscopic tumor incidence and tumor growth by age. Tumor size was estimated based on NIH images as shown by beige circles. Error bars, means ± SD. (C) Summary of histological atypia grades of tumors in AhR^−/− mice by age. AhR^+/+ (blue squares), AhR^+/− (green triangles), and AhR^−/− (yellow circles) are shown. AhR^−/− mice with adenocarcinomas (Grade 5) that had invaded the submucosal region or beyond (red circles) and within the intramucosal region (pink circles) are shown separately. (D) Representative H&E staining profile of a moderately differentiated adenocarcinoma and immunohistochemical staining with an antibody against β-catenin or c-myc.