HER2 status in sinonasal intestinal-type adenocarcinoma.

Given that the prognosis of patients with sinonasal intestinal-type adenocarcinoma (ITAC) has not significantly changed recently, there is a desire for new therapeutic approaches to improve clinical management. HER2-targeted therapy has remarkably improved the overall survival of patients with HER2 amplified tumors. To date, HER2 assessment has produced contradictory results in ITAC. The aim of this study was to assess HER2 status at both protein and DNA levels in a large series of ITAC. HER2 status was assessed by immunohistochemistry (IHC) and chromogenic in situ hybridization (CISH) in forty-three patients that underwent surgical resection for ITAC at the Otorhinolaryngology Section, Padua University Hospital, between 2007 and 2016. IHC was evaluated using the four-tier score developed for gastroesophageal cancer. As for IHC, 83.7% (36/43) of ITAC were scored 0, 14% (6/43) 1+, and 2.3% (1/43) 2+. No HER2 amplification was detected by CISH. The present is the largest study of sinonasal ITAC tested with both IHC and CISH confirmation for HER2 status. No HER2 overexpression/amplification was detected. Contrary to previous studies, our findings seem to rule out any oncogenetic role of HER2 in ITAC pathogenesis.