The contractor will perform a nested case-control study consisting of pancreas cancer cases diagnosed among women enrolled in WHI Observational Study (OS) and individually matched cancer-free controls, designed to identify biomarkers for the early detection of infiltrating pancreatic ductal adenocarcinoma (PDA). Plasma samples will be interrogated using a novel, high-density antibody microarray platform developed by its laboratories. The contractor will utilize methodologies that permit a highly cost effective approach to interrogate a broad dynamic range of the plasma proteome utilizing very small sample volumes (100-200 ul) while obtaining reliable comparative data on thousands of proteins simultaneously. In addition, the contractor will incorporate known and postulated risk factors for pancreas cancer in models designed to improve the performance of a plasma marker(s) to detect disease early.