PURPOSE: The breast cancer resistance protein (BCRP) is involved in in vitro multidrug resistance and was first identified in the breast cancer cell line MCF7/AdrVp. The aim of this study was to investigate the role of BCRP in resistance of breast cancer to anthracycline treatment. EXPERIMENTAL DESIGN: BCRP mRNA was determined with real-time reverse transcription-PCR and immunostaining in nine breast cancer cell lines and in samples of 25 primary breast carcinomas and 27 patients who received preoperative anthracycline-based therapy. Tumor response to treatment and patient survival were recorded. RESULTS: In cell lines, only MCF7 and BT20 had BCRP mRNA levels coinciding with membrane-bound immunostaining. In clinical samples, BCRP expression varied widely (range, 0.01-0.86). With immunohistochemistry, BCRP was detected in vessels and normal breast epithelium but not in tumor cells. There was no difference in BCRP expression between anthracycline-naïve and treated tumor samples. BCRP expression was not associated with decreased response or survival. CONCLUSIONS: There is no indication that elevated BCRP expression in breast carcinomas confers resistance to anthracyclines. Expression was not detectable with immunohistochemistry.
PURPOSE: The breast cancer resistance protein (BCRP) is involved in in vitro multidrug resistance and was first identified in the breast cancer cell line MCF7/AdrVp. The aim of this study was to investigate the role of BCRP in resistance of breast cancer to anthracycline treatment. EXPERIMENTAL DESIGN:BCRP mRNA was determined with real-time reverse transcription-PCR and immunostaining in nine breast cancer cell lines and in samples of 25 primary breast carcinomas and 27 patients who received preoperative anthracycline-based therapy. Tumor response to treatment and patient survival were recorded. RESULTS: In cell lines, only MCF7 and BT20 had BCRP mRNA levels coinciding with membrane-bound immunostaining. In clinical samples, BCRP expression varied widely (range, 0.01-0.86). With immunohistochemistry, BCRP was detected in vessels and normal breast epithelium but not in tumor cells. There was no difference in BCRP expression between anthracycline-naïve and treated tumor samples. BCRP expression was not associated with decreased response or survival. CONCLUSIONS: There is no indication that elevated BCRP expression in breast carcinomas confers resistance to anthracyclines. Expression was not detectable with immunohistochemistry.
Authors: T Nakanishi; S Chumsri; N Khakpour; A H Brodie; B Leyland-Jones; A W Hamburger; D D Ross; A M Burger Journal: Br J Cancer Date: 2010-02-09 Impact factor: 7.640