Expression of Breast Cancer Resistance Protein (BCRP-1) in canine mammary adenocarcinomas and adenomas.

Abstract

BACKGROUND: Among the recognized factors which induce multi-drug resistance, an increased activity of proteins belonging to the ATP-binding casette family, including breast cancer resistance protein 1 (BCRP-1), is regarded as the most important. Localization and intensity of BCRP-1 expression was evaluated in mammary adenocarcinomas and adenomas in dogs. The obtained results were compared to the grade of malignancy (G) of the tumours. MATERIALS AND METHODS: Materials for the study were sampled in the course of surgery from 54 dogs, of various breeds, aged 6 to 16 years (36 cases of mammary adenocarcinoma and 18 cases of mammary adenoma). The tumours were histopathologically verified and immunohistochemical reactions were performed to evaluate expression of BCRP-1. The microscopic patterns were photographed and subjected to computer-assisted analysis taking advantage of MultiScanBase Ver. 14.02 software. RESULTS: Expression of BCRP-1 was detected in over 85% of adenocarcinomas and almost 28% of adenomas. Samples of tumours with a higher grade of malignancy demonstrated an increased expression of BCRP-1. The two variables manifested a moderate positive correlation (r=0.35; p<0.05). CONCLUSION: The results point to a role of BCRP-1 protein in biology of tumour cells in dogs.