University of Tehran Press Journal of Veterinary Research 2008-2525 58 3 2003 10 23 - - 11921 FA Journal Article Objective: In this research, immunohistochemical method was used to study estrogen and progestrone receptors in canine mammary gland tumors. Animals: Six dogs with mammary gland tumors. Procedure: six out of 141 paraffin embedded blocks of canine mammary gland tumors, were selected from files of veterinary pathology department, faculty of veterinary medicine, Tehran university. Tissue samples were processed then H&E and immunohistochemistry staining carried out on sections. Results: Neither of species showed positive reaction to oestrogenic receptor nor progestronic receptor. Conclusion: Reasons for negative reactions may be one of these situations: malignancy of tumors, destruction of antigens in processing of tissues. It is necessary to remind that human being tumor markers have been used on uterus of horse with positive reaction to these hormones. Carcinoma is often observed with mixed tumors .Because of malignancy of carcinomatous tissues, there were no positive reactions. In this study ID5 monoclonal Ab for oestrogenic receptor and lA6 colon for progesteronic receptor have been used. J. Fac. Vet Med. Univ. Tehran. 58, 3: 283-285, 2003. Objective: In this research, immunohistochemical method was used to study estrogen and progestrone receptors in canine mammary gland tumors. Animals: Six dogs with mammary gland tumors. Procedure: six out of 141 paraffin embedded blocks of canine mammary gland tumors, were selected from files of veterinary pathology department, faculty of veterinary medicine, Tehran university. Tissue samples were processed then H&E and immunohistochemistry staining carried out on sections. Results: Neither of species showed positive reaction to oestrogenic receptor nor progestronic receptor. Conclusion: Reasons for negative reactions may be one of these situations: malignancy of tumors, destruction of antigens in processing of tissues. It is necessary to remind that human being tumor markers have been used on uterus of horse with positive reaction to these hormones. Carcinoma is often observed with mixed tumors .Because of malignancy of carcinomatous tissues, there were no positive reactions. In this study ID5 monoclonal Ab for oestrogenic receptor and lA6 colon for progesteronic receptor have been used. J. Fac. Vet Med. Univ. Tehran. 58, 3: 283-285, 2003. https://jvr.ut.ac.ir/article_11921_9ae5f16bbc85770e1dc3ef156762cec8.pdf