In addition, APC alterations have been found to be rarer in advanced duodenal carcinomas [8,9,10,11,19,20], suggesting that most NADAs have a low potential for malignant progression to duodenal adenocarcinomas and that the adenoma-carcinoma sequence may play a small role in the development of invasive duodenal adenocarcinomas. This evidence concerns the gene APC and adenoma.