Genomic profiling of ampullary adenocarcinoma (AA): Insights from a comparative analysis of pancreatic and intestinal adenocarcinoma and opportunities for targeted therapies use.

300Background: Ampullary adenocarcinoma (AA) is a rare entity. AA can originate from either intestinal or pancreaticobiliary ductal epithelium, and patients are often managed as those with pancreaticobiliary carcinomas. The study objectives were the genetic profiling of AA and the identification of specific molecular profiles according to these 2 pathological types. Methods: AA patients included in the AGEO retrospective multicenter cohort who underwent surgical resection of their tumor between 1999 and 2010 were selected. Formalin-fixed, paraffin-embedded (FFPE) archival tissue blocks were collected. Next generation sequencing (NGS) using a 50 gene panel (Ion AmpliSeq Cancer panel) on tumor DNA, and immunohistochemistry (IHC) panel including CK7, CK20, MUC1, MUC2 and CDX2, on tumor sections, were performed. Results: NGS was performed on 101 tumors from 6 hospitals, with 1 technical failure. In total, the most frequent gene mutations were: KRAS(45%), TP53 (40%), APC (15%), PIK3CA (12%), SMAD4 (9%), BRAF ...