SERPINB5 and breast cancer: SERPINB5 protein (also known as maspin, mammary gland-associated serine protease inhibitor) is a pro-apoptotic tumor suppressor that is completely suppressed in most breast cancers but is re-expressed on anti-cancer treatment [40], whereas the BIRC5 protein (also known as survivin), belongs to the Inhibitors of Apoptosis Protein (IAP) family, which is mostly absent from well-differentiated, normal adult tissues, but is over-expressed in nearly all human cancers [41].