Multidrug resistance associated genes MRP1, MRP2 and MRP3 in primary and anthracycline exposed breast cancer.

Background: Multidrug resistance associated proteins MRP1, MRP2 and MRP3 confer in vitro multidrug resistance. We investigated their role in breast cancer resistance to anthracycline-based chemotherapy.

Materials And Methods: Using real-time reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry (IHC), the expression of MRP1 - 3 was quantified in nine breast cancer cell lines and 30 breast carcinoma samples.

Association of C-MYC amplification with progression from the in situ to the invasive stage in C-MYC-amplified breast carcinomas.

Human carcinoma in situ of the breast already demonstrates genomic changes found in invasive lesions. However, no specific genetic alterations have previously been identified that are associated with progression from the in situ to the invasive stage. By comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH) analysis of an invasive breast carcinoma with a large associated in situ component, high-level amplification of C-MYC was found in the invasive component only.

Expression of the breast cancer resistance protein in breast cancer.

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.