Determining the expression levels of circulating tumour cell markers in canine mammary tumours

Zeynep Günay Uçmak,Kazım Güvenç,Sevgin Değirmencioğlu,İlhan Yaylım,Güldal İnal Gültekin,Özlem Timirci Kahraman

doi:10.2754/avb202190020191

Abstract

Detection of the circulating tumour cells (CTC) in dogs with a mammary tumour is a useful tool to reveal the micrometastases long before metastases are recognised clinically. The aim of this study was to evaluate the association of the epidermal growth factor receptor (EGFR), claudin 7 (CLND7) and epithelial cell adhesion molecule (EPCAM) with the clinical indices and to reveal the diagnostic importance of these biomarkers in canine mammary tumours (CMTs). Peripheral blood (PB) samples were collected from 45 bitches (group MT) which had single mass with malignant epithelial tumours and 9 healthy bitches (group H). Real time PCR (rt-PCR) was performed to determine the expression levels of EGFR, CLDN7, and EPCAM. Mean values of EGFR and CLDN7 expressions were significantly higher in group MT compared to group H (P < 0.01 and P < 0.001, respectively). The expression level of CLDN7 was positively correlated with EGFR and EPCAM (P < 0.001 and P < 0.05, respectively). The EPCAM expression was associated with increased tumour size (P < 0.05) and EPCAM tended to decrease in the presence of skin ulceration on tumour (P = 0.05). Furthermore, expression levels of EGFR in intact dogs were significantly higher compared to spayed dogs in group MT (P < 0.01). The EGFR expression was significantly higher in the presence of metastases (P < 0.05). Also, increased EGFR was determined in grade 2 compared to grade 1 (P < 0.05). In conclusion, these results show that EGFR, CLDN7, EPCAM markers are measureable in PB and they may provide valuable information about the clinical pathophysiology of CMT.

Highlights

Metastatic risks in canine mammary tumours (CMTs) are determined depending upon several clinical prognostic factors such as the tumour type, histological differentiation, and tumour size (Ferreira et al 2009)
Identification of circulating tumour cells (CTC) is a potential marker for understanding the clinical course of canine mammary tumours
epidermal growth factor receptor (EGFR) and claudin 7 (CLDN7) were detected in circulation by Real time PCR (rt-PCR) assay

Summary

Introduction

Metastatic risks in canine mammary tumours (CMTs) are determined depending upon several clinical prognostic factors such as the tumour type, histological differentiation, and tumour size (Ferreira et al 2009). There were several reports on tissue expression of EGFR (Gama et al 2009; Carvalho et al 2013; Guimarães et al 2014) and CLDN7 (Jakab et al 2008; Hammer et al 2016) in CMTs. e-cadherin was usually expressed in tissue as cell adhesion molecule in CMTs but in human breast cancer EPCAM expression was evaluated as a cell adhesion molecule (Gao et al 2017). Detection of the CTC markers from the peripheral blood (PB) of dogs with a mammary tumour in the pre-operative term may be a useful tool for early diagnosis of CMTs. The aim of this study was to investigate the expression levels of EGFR, CLDN7, and EPCAM in PB. The relationship between the clinical indicators (ovariohysterectomy [OVH] status, histology types, histology grade, metastases, ulceration and necrosis) and the circulated tumour markers (EGFR, CLDN7, EPCAM) in dogs with mammary tumor were explored

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