Evaluation of hormone receptor expression for use in predicting survival of female dogs with malignant mammary gland tumors.
OBJECTIVE
To evaluate the prognostic potential of expression of hormone receptors in malignant mammary gland tumors of dogs. Design-Cohort study.


METHODS
89 female dogs with malignant mammary gland tumors and 24 female dogs with benign mammary gland tumors.


METHODS
Female dogs with malignant (n = 89 dogs) and benign (24) mammary gland tumors were evaluated to determine the prognostic value of the expression of estrogen receptor (ER)A or the progesterone receptor (PR), as determined by use of immunohistochemical methods.


RESULTS
In this study, 68 (60.2%) and 88 (77.9%) of the 113 dogs with mammary gland tumors had expression of ERA and PR, respectively. Expression of ERA and PR was detected proportionately more frequently in benign tumors (23/24 [95.8%] and 24/24 [100%], respectively) than in malignant tumors (45/89 [50.6%] and 64/89 [71.9%]). Percentage of tumors with positive results for ERA and PR was significantly higher in tumors < 5 cm in diameter; as clinical stage I, II, or III; and without metastasis to lymph nodes or distant metastasis. However, only PR expression in tumor cells was significantly associated with 1-year survival after surgical removal of the tumor. Moreover, dogs with malignant tumors expressing ERA and PR had a significantly higher survival rate, compared with the rate for dogs with malignant tumors expressing ERA but not PR.


CONCLUSIONS
These findings strongly suggested that expression of PR could be used as a prognostic factor for survival, especially in female dogs with malignant mammary gland tumors with ERA expression.
Chang
Chao-Chin
CC
Graduate Institute of Microbiology and Public Health, College of Veterinary Medicine, National Chung Hsing University, Taichung, Taiwan.
Tsai
Min-Hsuan
MH
Liao
Jiunn-Wang
JW
Chan
Jacky Peng-Weng
JP
Wong
Min-Liang
ML
Chang
Shih-Chieh
SC
D000818:Animals; D015331:Cohort Studies; D004283:Dog Diseases / Q000378:metabolism* / Q000401:mortality* / Q000473:pathology; D004285:Dogs; D047628:Estrogen Receptor alpha / Q000378:metabolism*; D005260:Female; D007150:Immunohistochemistry / Q000662:veterinary; D008207:Lymphatic Metastasis; D015674:Mammary Neoplasms, Animal / Q000378:metabolism* / Q000401:mortality* / Q000473:pathology; D009367:Neoplasm Staging / Q000662:veterinary; D011237:Predictive Value of Tests; D011379:Prognosis; D011980:Receptors, Progesterone / Q000378:metabolism*; D015996:Survival Rate
D047628:Estrogen Receptor alpha; D011980:Receptors, Progesterone