Patients and Tumor Samples

Breast cancer cohort I includes 564 pre-menopausal patients, enrolled in a trial from 1986 to 1991 and randomized to either 2 years of adjuvant tamoxifen treatment (n = 276) or no systemic treatment (n = 288). All patients were followed up for recurrence-free survival. Recurrence was defined as local, regional, or distant recurrence and breast cancer-specific death, whereas contralateral breast cancer was excluded. Each patient underwent surgery (either modified radical mastectomy or breast conserving surgery) followed by radiotherapy and in a small number of cases adjuvant polychemotherapy (less than 2%). The median post-surgery follow-up time without a breast cancer event was 13.9 years. Further details of the trial have been previously described [13], [14]. Breast cancer cohort II includes 179 pre- and post-menopausal patients undergoing endocrine or chemotherapy, diagnosed with primary invasive breast cancer between 2000 and 2002, at the Department of Pathology, Malmö University Hospital. This cohort was designed as a first-line screening cohort for Human Protein Atlas (HPA) antibodies with potential relevance in breast cancer [15]. Median age at diagnosis was 65 years (range 35–97) and median follow-up time 69 months. All patients in this cohort had received treatment following surgery. For detailed description of clinico-pathological features of the tumor samples we refer to previous studies [16], [17]. Representative tumor areas of formalin-fixed and paraffin-embedded tissue material were selected for tissue microarray (TMA) construction. Details regarding TMA assembling and staining procedure have been reported [13].