Positive correlation of steroid hormones and EGF in canine mammary cancer

There are no published studies focused on the potential crosstalk between steroid hormones and EGF in canine mammary tumourigenesis. The objective was to investigate the role of EGF in canine mammary tumours (CMT) and the relationship with steroid hormones. Sixty-three CMIT (39 malignant including 10 inflammatory mammary carcinomas (IMC); 19 benign and 5 dysplasias), and 13 normal mammary glands from dogs without history of neoplastic disease were analysed. Levels of EGF and steroid hormones [progesterone (P4); 17 beta-estradiol (E2); androstenedione (M) and dehydroepiandrosterone (DHEA)], were analysed by EIA in CMT homogenates. Levels of EGF were significantly higher in malignant compared with benign tumours, dysplasias and normal mammary glands (p < 0.001). IMC presented the highest EGF levels, with statistical significant difference between IMC and non-IMC cases (p < 0.05). Steroid hormone levels were also significantly higher in malignant tumours compared with benign tumours, dysplasias and normal mammary glands (p < 0.001). In malignant tumours (non-IMC and IMC), a strong correlation was observed between EGF and: P4 (r = 0.452; p = 0.003); E2 (r = 0.624; p = 0.023); A4 (r= 0.496; p = 0.038); DHEA (r = 0.431; p = 0.005). These results suggest that EGF is implicated in canine mammary tumourigenesis. The positive correlation observed, opens an interesting perspective of interaction that should be further investigated. (c) 2009 Elsevier Ltd. All rights reserved.