Loss of expression identifies pancreatic ductal adenocarcinoma as well as some tumors of the ampulla and colon, and SMAD4 is a useful marker for the workup of carcinoma of unknown primary.
• Formalin-fixed, paraffin-embedded (FFPE) tissue block or cell block - OR - • 3 unstained slides for each test requested plus 1-2 additional unstained slides cut at 4µm