Marcadores tumorais séricos e expressão gênica de receptores hormonais em neoplasias mamárias caninas

Abstract

The present objective was to perform a clinical and histopathological study to investigate the serum levels of estradiol, progesterone and prolactin, as well as the gene expression of the estrogen receptors α and β, and progesterone in bitches with mammary tumors. Sixty bitches of various ages and breeds were selected: 30 with mammary neoplasia and 30 healthy bitches. Fragments of the tumors were collected for histopathology and for investigation of the gene expression of the hormone receptors. Serum samples were also collected for measurement of serum hormones and Ca15.3. Malignant neoplasms were more frequent (76.6%), with a greater number of carcinosarcomas (36.7%). The frequency of benign tumors was 23.3%. Mammary tumors were mostly multiple, larger than 5 cm, and located in the abdominal mammary glands. Owners reported that most dogs had not shown signs of pseudocyesis, had not had a prior pregnancy, nor had they used contraceptives or been spayed. Regarding serum concentrations of the Ca15.3 marker, there was no difference when comparing bitches with neoplasia and healthy bitches, or when comparing the other groups. Bitches with malignant neoplasms had higher levels of estradiol and lower levels of prolactin. Both malignant and benign neoplasms expressed hormone receptors, and there was no difference in expression between them. There was also no difference in prognostic factors between groups. Serum levels of estradiol increased significantly with clinical staging of the disease. There was also a moderate negative correlation between serum levels of estradiol and prolactin. It is concluded that the hormonal influence is evident in cases of canine mammary neoplasms, especially estrogens, which seem to be most associated with malignant characteristics. The influence of hormones is reinforced by the presence of hormone receptors even in different tumor types, which could suggest the use of hormone therapy as an alternative. However, quantification of Ca15.3 did not show any results that made its use possible as a tool for patient monitoring and evaluation.