Occurrence of Spontaneous Mammary Intraepithelial Neoplasia in the Canine Mammary Glands and Estrogen Receptor Reactivity

Abstract

Intraepithelial neoplasia is a significant precancerous lesion that poses a high risk of developing into clinical cancer. The prevalence and association of mammary interaepethial neoplasia (MIN) and spontaneous canine mammary cancer have not been investigated. The purpose of this study is to determine the prevalence of MIN and its association with spontaneous canine mammary carcinoma. Formalin-fixed tissues from 13 normal dogs and 20 dogs with mammary carcinoma were evaluated for the presence of MIN. Estrogen receptor status was examined by immunohistochemistry; the original Estrogen Receptor protocol designed for humans proved ineffective, however, strong staining was eventually achieved. From this pilot study we could conclude that MIN is present in canine mammary carcinoma. These results indicate that canine mammary carcinoma could serve as a model for breast cancer development and progression. Different chemoprevention strategies could be used to targets MIN in canine mammary cancers.