Histological appearance of normal (A), BPH (B) and PCa canine prostate tissues incorporated in this study. In the normal prostate continuous sheets of epithelial cells (ec) are separated by connective tissue stroma (S) consisting of blood capillaries (indicated by closed arrows), smooth muscle and neuroendocrine cells. BPH glands display smaller lumens (L) compared to normal tissue with evidence of tufting and micropapillae. PCa glands are lined with neoplastic cells exhibiting cellular and nuclear pleomorphisms and numerous mitotic figures (open arrows). The basal cells (bc) were irregular in contour but the basement membrane appears confluent. Original magnifications: × 400.