Spontaneous Mammary Carcinomas in Female Dogs: Association between the Immunohistochemical Degree of Aggressiveness of Tumors, Intensity of DNA Damage and Residues of Pyrethroids

Abstract

Diagnosis and biological behavior of breast cancer of female dog represent one of the biggest challenges facing the Veterinarian in recent years. Due to its exponential growth and the degree of aggressiveness, the exact cause of this tumor is probably multifactorial and it is believed that may suffer influence from environmental factors. Among the suspected environmental contaminants are the pyrethroids. Aiming to investigate the participation of pyrethroids in tumorigenesis in female dogs, a study was conducted using 50 female dogs, 22 were positive for simple breast carcinoma (Group I), 18 with a diagnosis of complex breast carcinoma (Group II) and 10 negative (Group III) for breast cancer. In order to detect DNA damage, the Comet assay was performed on mammary samples of these animals, which also had samples submitted to the technique of High Performance Liquid Chromatography (HPLC), which aimed to quantify the concentration of pyrethroids. The results of HPLC of each animal were compared with those obtained by the Comet assay analysis of variance and the means were compared by the test groups "Student T" at the significance level of p  0.05. Despite presenting correlation between the amount of DNA damage and tumor aggressiveness, no statistical differences were found in the DNA damage of different histologic types of breast carcinoma. As for pyrethroids, even these were detected in 22% of tumor tissues and peritumoral fat, there was no difference in DNA damage between cells exposed and not exposed to environmental contaminant.

A modern look at the molecular-biological mechanisms of breast tumours in dogs

“…Changes in exons 5-8 of the p53 gene suppressor were found in 11% of benign tumours and 25% of malignancies, indicating their probable initiation at early stages of carcinogenesis, but there is no evidence of their correlation with histological type (Muto et al, 2000). Brandão et al (2013) against the background of the correlation between the amount of DNA damage and the aggressiveness of neoplasia, did not find statistical difference of DNA mutations for different types of breast cancer. The most common cellular and molecular processes involved in tumour progression are non-coding RNAs, epigenetic modifications, and immune responses.…”

Aspectos Epidemiológicos Associados Às Neoplasias Caninas No Município De Patos/Pb / Epidemiological Aspects Associated With Canine Neoplasms in the Municipality of Patos/Pb

“…Muitos são os fatores de risco implicados no desenvolvimento do câncer. Isoladamente ou em combinação, exposições a determinadas substâncias químicas como ácidos, tintas, piretróides, amianto, tabaco (BRANDÃO et al, 2013;ANDRADE et al, 2010); alimentares: ingestão de alimentos ricos em gordura e obesidade (ALENZA et al, 1988;KELSEY et al, 1998); ambientais: radiação eletromagnética, radiação solar e herbicidas (ANDRADE et al, 2012;GAVAZZA et al, 2001) e biológicas: doenças virais e fatores genéticos (GAVAZZA et al, 2001;KELSEY et al, 1998), têm demonstrado destaque como fatores de risco de neoplasias em cães.…”