The canine prostate is a spontaneous model of intraepithelial neoplasia and prostate cancer progression.

Increasing evidence suggests that high grade prostatic intraepithelial neoplasia (PIN) represents a precancerous stage in the morphologic continuum of progression from benign epithelium to carcinoma. In this report, we summarize our work characterizing the high grade PIN that occurs spontaneously in the canine prostate. The similarity between canine and human PIN for basal cell layer disruption, proliferative index, microvessel density, and its association with carcinoma suggest that the canine prostate may be a useful model for studying carcinogenesis and cancer progression.