Reverse phase protein array based protein profiling of breast cancer specimens

Expression levels of proteins and phosphoproteins, covering major cancer signaling pathways with a special focus on breast cancer biology, were obtained for a series of 109 breast cancer tumor specimens with positive estrogen receptor status. Tumor specimens from patients diagnosed with primary invasive breast carcinoma were collected at the time of surgery between 2008 and 2010 at the Department of Gynecology and Obstetrics / National Center for Tumor Diseases Heidelberg. None of the patients had received neoadjuvant therapy. Institutional Review Board approval was received as ethics vote no. S039/2008 and informed consent was obtained from all patients. Tumor specimens were processed within 20 min after surgery. Samples were stored snap frozen at -80°C until further use. Only tumor samples with > 70% tumour cells and positive estrogen receptor status (immunoreactive score ≥ 3) as assessed by routine immunohistochemistry were selected for this study (n = 109). Tumor lysates were printed on a series of nitrocellulose coated glass slides and probed with 128 different primary antibodies directed against proteins and phosphoproteins of interest. Primary antibodies were selected to recognize proteins involved in major cancer signaling pathways with a special focus on breast cancer biology.