Correlation of Her2 Protein Expression and Gene Amplification between Endoscopic and Surgical Specimens of Gastric Cancer
Cigdem Irkkan, Serdar Balci, Gaye Guler Tezel, Bulent Akinci, Bulent Yalcin, Gulnur Guler. Yildirim Beyazit University, Ankara, Turkey; Hacettepe University, Ankara, Turkey
Background: Reported incidence of Her2 expressing gastric carcinoma is between 6-35%. Recent phase III trial has shown the survival benefit in metastatic gastric carcinoma treated with anti-Her2 therapy. Because of reported heterogenous expression pattern of Her 2 in gastric carcinoma, predictive power of endoscopic biopsies in determining the Her2 status is an important issue. Correlation of Her2 status determined by both immunohistochemistry (IHC) and In situ hybridisation (ISH) techniques in endoscopic biopsies (EB) and gastrectomy specimens (GS) was the aim of this study.
Design: GS and previous EB from 42 gastric tumors in our database are retrospectively searched for their Her2 status by clone:4B5 IHC and Brightfield Dual Silver ISH techniques. Both techniques are performed on the same automated platform (Ventana, Benchmark GX). Heterogenity of Her2 IHC staining was categorised as dispersed or clustered in both EB and GS.