ERBB2 and gastric cancer: In order to identify ERBB2-amplified cases as reliably as possible, we propose a simultaneous immunohistochemical and cytogenetic approach: the use of the ASCO/ACP evaluation mode for ERBB2 immunoscoring in GC, since the 2+ UTUC cases in particular often only show incomplete basolateral staining, combined with ERBB2 FISH or CISH analysis.