HER2 in resected gastric cancer: Is there prognostic value?

Background and Objectives The role of HER2 in patients with early stage/resected gastric cancer is controversial. This study investigates the prevalence and prognostic value of HER2 in patients undergoing curative intent resection for gastric adenocarcinoma. Methods HER2 status was evaluated in 111 patients with gastric adenocarcinoma treated surgically between 1/00 and 6/11 with tissue available for analysis. Immunohistochemistry (IHC) for HER2 was graded by two blinded pathologists. IHC was scored as 0+/1+: negative, 2+: equivocal, and 3+: positive. Fluorescence in situ hybridization (FISH) for HER2 was performed on equivocal (2+) samples, and in cases of pathologist disagreement. Results HER2 expression as measured by IHC was negative in 61 (55%), equivocal in 37 (33.3%), and positive in 13 (11.7%) cases. FISH was positive in 8 of 37 samples tested, for a total of 21 HER2-positive cases (18.9%, 95% CI 11.6-26.2%). Patients with HER2-positive tumors were less likely to have signet ring cell features (23.8% vs. 53.9%, P = 0.008). HER2 status was not associated with tumor size, location, perineural or lymphovascular invasion, margin status, nodal metastasis, or stage (P > 0.05). HER2 status was not associated with OS (P = 0.385). Conclusions HER2 amplification/over-expression is present in patients with resected gastric adenocarcinoma, but is not associated with the presence of adverse prognostic factors. Our results suggest HER2 is not prognostic for patients with resected gastric adenocarcinoma. J. Surg. Oncol. 2014 109:61-66.