Apoptosis in the ventral and dorsolateral prostates of SV-40 Tag and non-transgenic rats fed control AIN-76A diet, starting at day one. Each age group had at least 3 transgenic and 2 non-transgenic animals per group. Values are presented as total number of apoptotic epithelial cells divided by total number of epithelial cells × 100 ± SEM. Picture inserts are examples of brown staining for apoptotic cells in ventral prostates of 32 week old A) non-transgenic rats and B) SV-40 Tag rats. In A: a normal prostatic duct lined by cuboidal-to-columnar epithelial cells that have abundant cytoplasm and uniform non-overlapping nuclei (green staining). There are infrequent apoptotic cells (brown staining – arrow). In B: numerous apoptotic bodies with solid mass of tumor, minimal glandular formation, nuclear crowding and cells with high nuclear cytoplasmic ratio.