miRNA expression profiles of primary ER-positive breast tumors following Tamoxifen treatment

Adjuvant tamoxifen is a valid treatment option for women with estrogen receptor (ER)-positive breast cancer. However, up to 40% of patients experience distant or local recurrence or die. MicroRNAs have been suggested to be important prognosticators in breast cancer. This study aims to identify microRNAs with the potential to predict tamoxifen response. We performed a global microRNA screen in primary tumours of six matched pairs of postmenopausal, ER-positive breast cancer patients treated with tamoxifen, who were either recurrence free or had developed a recurrence. Patients were treated at the Robert Bosch Hospital, Stuttgart, Germany, between 1986 and 2005. Total RNA from FFPE tissue from 12 postmenopausal patients with ER-positive breast cancer (6 patients with and 6 patients without recurrence) was extracted. Hybridisation of biotin-labelled RNA was performed on Affymetrix GeneChip miRNA_2.0 Arrays.