In situ protein expression of RRM1, ERCC1, and BRCA1 in metastatic breast cancer patients treated with gemcitabine-including chemotherapy

1129 Background: Ribonucleotide reductase 1 (RRM1) is a determinant of gemcitabine efficacy in non-small cell lung cancer (NSCLC) and pancreatic cancer. We investigated the tumoral levels of RRM1 in a population of metastatic breast cancer (MBC) patients treated with gemcitabine-based regimens. The protein levels of the excision repair cross-complementation group 1 (ERCC1) and breast and ovarian cancer susceptibility gene 1 (BRCA1) were also measured. Methods: Fifty-five patients were treated and followed prospectively from September 2004 to December 2007. Treatment consisted of gemcitabine plus a taxane in 46 patients and gemcitabine plus pegylated liposomal doxorubicin in 9 patients. RRM1, ERCC1, and BRCA1 were determined by automated in situ protein quantification (AQUA v1.6) on a tissue microarray containing triplicate tumor specimens. Results: The average scores for RRM1, ERCC1, and BRCA1 ranged from 245.6–2, 774.1, 74.0–410.3, and 54.4–1, 833.1, respectively. A statistically significant correlation ...