SMAD4

Formalin-fixed, paraffin embedded tissue block or cell block, or 1 unstained charged slide for each test requested plus 3-4 additional unstained slides cut at 4 microns. Adequate space on each slide for control tissue is required.

Smad4 is a tumor suppressor gene located at 18q21.1. It is inactivated in 55% of pancreatic adenocarcinomas and in 34% of carcinomas of the Ampulla of Vater but not in ampullary adenomas. Inactivation is manifested by loss of nuclear expression by immunohistochemistry.