A co-expression study evaluated the expressions of HER2, EGFR, MET, and FGFR2 using tissue microarrays (TMAs), immunohistochemistry (IHC), and FISH of 950 patients with gastric adenocarcinoma, detecting FGFR2 positivity in 31% of cases using TMAs but with most of the FGFR2-positive tumors only showing strong staining in IHC in between 10 and 30% of the IHC staining area. The gene discussed is ERBB2; the disease is gastric adenocarcinoma.