Abstract
Steroid hormones are found to play a major role in the genesis and progression of mammary tumors. The aim of this study was to immunohistochemically detect the presence of estrogen receptor alpha (ERα), estrogen receptor beta (ERβ), and progesterone receptor (PR) and also to study the association between these markers in 29 cases of benign (11) and malignant (18) canine mammary tumors. ERα immunostaining was noticed in only one case of carcinosarcoma specifically in the nuclei of epithelial and a few myoepithelial cells. ERβ immunostaining was noticed in the nuclei and cytoplasm of epithelial cells and smooth muscles lining the blood vessels. Immunoexpression of ERβ was 82% in benign tumors and 78% in malignant tumors. PR immunostaining was expressed in the nuclei of epithelial cells in both benign and malignant tumors. Among the 15 PR+ cases, 6 (55%) were of benign type, and 9 (50%) were of malignant type. The most common group of hormone receptor was the ERα−/PR+/ERβ+ (46%) in benign tumors and ERα−/PR−/ERβ+ (38%) in malignant tumors. Although there was no significant association between ERα and PR with ERβ, the findings indicated that ERβ was consistently expressed in both benign and malignant tumors, irrespective of ERα and PR status.
Highlights
Mammary gland tumors are among the most common neoplasms in dogs and have been reported worldwide
Localization of ERα, ERβ, and progesterone receptor (PR) was restricted to the nucleus of cells in all cases of positivity
Steroid hormones have been reported to play a key role in the development of mammary neoplasms [8]
Summary
Mammary gland tumors are among the most common neoplasms in dogs and have been reported worldwide. The majority of mammary neoplasms in female dogs are of epithelial origin, and approximately 50% of them are malignant [1]. These neoplasms have a complex morphology in forming epithelial, mixed, and mesenchymal types [2]. There are only limited reports on clinical utilization of proliferation markers and steroid receptors in canine mammary neoplastic conditions [5]. Both estrogen and progesterone are mitogenic by autocrine or paracrine mechanisms. Since steroids regulate the expression of certain cyclins or kinase inhibitors, they may control cell-cycle progression directly [6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
