Expression of epidermal growth factor receptor (EGFR) in non-affected and tumorous mammary tissue of female dogs

Abstract

Epidermal growth factor (EGFR), oestrogen (ER), and progestin (PR) receptor concentrations were determined by radioligand binding assay in non-affected mammary tissues (n = 13) and benign (n = 11) and primary/locally recurrent malignant proliferative mammary lesions (n = 45) and metastases (n = 19) in 65 female dogs. The number of specimens expressing EGFR was not significantly different among these tissues, but EGFR concentration was lower in metastases (P = 0.02) than in benign or primary/locally recurrent malignant lesions not mixed with non-affected mammary tissue. The presence of non-affected mammary tissue in primary cancer specimens was noticed as a factor that may influence results of receptor measurements. No relation was found between the expression of EGFR and that of ER or PR in non-affected or in tumorous mammary tissues. It was concluded that in the dog mammary gland EGFR expression is not associated with conditions of steroid receptor absence of biological agressiveness of neoplastic growth.

Sialylation regulates galectin-3/ligand interplay during mammary tumour progression - a case of targeted uncloaking

“…Moreover, in our study, EGFR expression was significantly associated to the presence of necrosis in CMMT. In accordance, in a previous work, EGFR expression was thoroughly studied by ligand binding in a series of canine normal mammary tissue, benign and malignant tumours and although no statistical differences were found between the levels of expression of the receptor between non-tumorous tissues and CMMT (Rutteman et al, 1994), when analysing EGFR by autoradiography, a high level of activity in necrotic areas was found (Berns and Rutteman, unpublished data). Similarly, increased galectin-3 expression around necrotic (hypoxic) areas has also been reported in CMT (de Oliveira et al, 2010) and in human cancer (Neder et al, 2004).…”

EGFR and microvessel density in canine malignant mammary tumours

“…In canine mammary tumours (CMT), studies regarding EGFR immunoexpression and/or content are scarce. There is a limited number of old reports based on different methodologies, demonstrating the presence of EGFR in mammary gland tissues and neoplasias (Nerurkar et al, 1987;Donnay et al, 1993Donnay et al, , 1996Rutteman et al, 1994) and more recent works that indicate the link between EGFR immunoexpression and high tumoural aggressiveness (Gama et al, 2009;Kim et al, 2013). A study, which was recently carried out by our team, in a small series of cases (n = 43), showed a link between EGFR immunoexpression and more aggressive tumour phenotypes (Guimarães et al, 2013).…”

Epidermal growth factor receptor as a therapeutic target in veterinary oncology

“…EGFR expression has been characterized in the normal mammary gland of dogs 50,53,54 . EGF and EGFR expressions have also been evaluated for possible roles in disease classification and pathogenesis in these species 50–52,54–56 . As in man, variations in methods used to evaluate EGFR expression and in patient sampling have led to discordant results that are difficult to compare directly 47,50 .…”

“…As in man, variations in methods used to evaluate EGFR expression and in patient sampling have led to discordant results that are difficult to compare directly 47,50 . Rutteman et al 56 evaluated the concentration of EGFR in membrane aliquots of homogenized tissue samples from a range of cancerous and non‐cancerous mammary tissues from dogs with mammary tumours using a radioligand‐binding assay. In this study, no correlation of membranous EGFR concentration with tumour size, regional lymph node involvement, metastatic disease or tumour type was found and the authors concluded that EGFR expression was not associated with biological aggressiveness of canine mammary tumours 56 .…”

“…EGFR‐mediated signalling has been implicated as a mechanism enabling tumour cells to evade oestrogen‐targeted therapies leading to relapse and may explain inverse correlation between oestrogen receptors and EGFR in some breast cancer types 59 . Canine mammary tumours also express oestrogen and progesterone receptors and sex steroid receptor expression and activation are likely to be linked to the pathogenesis of disease 54–56 . EGFR expression and sex steroid expression have also been evaluated in canine mammary tumours 54,55,60 .…”