ABSTRACT:
The aim of this study was to evaluate the serum concentrations of estradiol, progesterone, prolactin, the gene expression of estrogen α and β and progesterone receptors in bitches with mammary neoplasms. Sixty adult crossbred bitches distributed in two groups were used. Group I consisted of 30 bitches with mammary neoplasms and Group II consisted of 30 healthy bitches without neoplasia. For the tutors, interviews were made about the disease epidemiology. After preoperative examinations, bitches with mammary neoplasia were submitted to mastectomy; fragments of the neoplasms and regional lymph nodes were collected and processed for histopathological analysis. Blood samples were collected in tubes without anticoagulant and the serum was analyzed by electrochemiluminescence to measure estradiol, progesterone and prolactin. The gene expression of the hormonal receptors was performed by means of the Real-time PCR technique, thus fragments of mammary neoplasms were collected and the RNA was extracted to obtain cDNA. Expression of the mRNA for ERα, ERβ and PR was assessed from the amplification of these genes using specific primers. Higher serum levels of estradiol (mean 38.98±13.68pg/mL) were observed in bitches with malignant neoplasms when compared to the control bitches (p<0.05). Serum prolactin levels were higher (mean of 0.231±0.201ng/mL) in bitches that did not have mammary neoplasms when compared to Group I (p<0.05). No difference was observed for related to the progesterone levels between the groups (p>0.05). Both malignant and benign tumors expressed ERα, ERβ and RP with no statistical difference (p>0.05) and there were no difference related to the other prognostic factors investigated (clinical staging, presence of ulceration, vascularization and aging of neoplasms). Serum estradiol levels increased significantly with the clinical staging of the disease (p<0.05). There was a moderate negative correlation between serum levels of estradiol and prolactin. It was concluded that serum levels of estradiol and PRL were influenced by tumor malignancy and clinical staging of neoplasms. Hormonal receptors were expressed by neoplasms, regardless of tumor type and are not associated with other classical prognostic factors, such as ulceration, vascularization or clinical staging.
INDEX TERMS:
Mammary neoplasm; serum concentration; hormones; estrogen; progesterone; bitches; breast tumor; prolactin; hormone receptor; clinics