ERBB2 and gastric adenocarcinoma: The frequency of HER2-positive tumors (IHC3 + or IHC2 + plus FISH-positive) is reported to be about 21% among patients with advanced or recurrent gastric adenocarcinoma, and 32% among patients with advanced or recurrent esophagogastric junction cancer; thus, there is a trend toward a higher frequency in patients with esophagogastric junction cancer [153].