IBSP and breast cancer: In bone metastases from breast cancer, including invasive ductal carcinoma, moderate to strong BSP protein is detected in 100% (n = 42) of tumour cells.50,73 In non-small cell lung cancer (NSCLC), BSP protein is present in 20% (6/30) of primary tumours versus 80% (24/30) of bone metastases, and in 31% (8/28) of non-bone metastases [e.g. liver, CNS, adrenal glands].74 Similarly, BSP protein is expressed in 100% (n = 9) of pancreatic ductal adenocarcinoma (PDAC) lymph node and liver metastases.69