Napsin A

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.

Identifying an adenocarcinoma as primary of the lung. It is strongly positive in up to 80% of primary lung adenocarcinomas by immunohistochemistry. Squamous cell carcinomas and small cell carcinomas of the lung have been negative for napsin A. However, 10% of renal cell carcinomas and thyroid carcinomas are also positive. Less than 5% of assorted adenocarcinomas, including those from the breast, pancreas, biliary tract, and colon stain with napsin A.