CLINICOPATHOLOGICAL EVALUATION OF ESTROGEN RECEPTOR, PROGESTERONE RECEPTOR, EPIDERMAL GROWTH FACTOR RECEPTOR AND CARBOHYDRATE ANTIGEN 15-3 IN CANINE MAMMARY TUMOUR

Mammary tumors are the most common neoplasms in unspayed female dogs. Biomarkers are biological molecules measured in blood or tissue that provide information for the presence of disease, treatment and prognosis. Tumor biomarkers can be used to determine cancer risk, early diagnosis, recurrence or progression. In this study, 125 tissue samples from 31 dogs with mammary tumor were included. It is aimed to evaluate the tissue estrogen receptor (ER), progesterone receptor (PR), epidermal growth factor receptor (EGFR) and carbohydrate antigen 15-3 (CA 15-3) in regard to different tumor types and clinicopathological parameters. Tumors included in the study; were evaluated in 3 groups as malignant epithelial tumors group (MET, n=66), hyperplasia&dysplasia (H&D, n=43) group and benign mammary tumor (BMT, n=16) group. The highest ER and PR levels were determined in group BMT (P<0.05). Also, CA 15-3 level in group MET was significantly higher than in group H&D (P=0.01). However, the evaluated biomarkers in group MET were not different with regard to clinicopathological parameters such as histological subtypes and grading, tumor size, and invasion (P>0.05). In this study, ER was moderately and positive correlated with PR (r=0.383, P<0.001) while it was low and positive correlated with EGFR (r=0.223, P<0.05). Also, CA 15-3 was moderately and positive correlated with EGFR (r=0.376, P<0.001) while it was low and positive correlated with PR (r=0.216, P<0.05). This study stated that ELISA is capable enough to detect the ER, PR, EGFR and CA 15-3 in canine mammary tumor tissue. In conclusion, ER and PR can distinguish benign tumor from malignant tumor and H&D, while CA 15-3 can distinguish malignant tumor from H&D.