Representative photomicrographs of the carcinogen-treated groups from the premalignant study. From L-R: whole mounts (40×, left panels), H&E's (200×, middle panels) and BrdU staining (200×, right panel). Genotype, treatment, and diets are indicated at each row: [A] WT/DMBA control diet; [B] WT/DMBA/AUR diet; [C] KO/DMBA control diet; [D] KO/DMBA/AUR diet. All photomicrographs were uniformly reduced in size to 70% of the original picture in order to fit into the figure panels. Note, in the BrdU study, some background staining occurred, but this was also detected in the no primary antibody control (data not shown). Nuclear staining of epithelial cells was not observed in the background control.