Is Helicobacter pylori a poor prognostic factor for HER-2 SISH positive gastric cancer?

BACKGROUND Helicobacter pylori (H. pylori) is one of the risk factors for gastric cancer (GC). Any prognostic effect of HER-2 status in gastric lymph node metastasis in H. pylori positive cases is unknown. MATERIALS AND METHODS A total of 74 patients, 47 (64%) male, and 27 (34%) female, who had subtotal or total gastrectomy and also positive lymph nodes, were included in the study. Age range was 29-87 years, and median age was 58 years. HER-2 expression was assessed in both gastric resection samples and lymph node material with carcinoma metastasis of the same patient by immunohistochemistry (IHC) and silver in situ hybridization (SISH) methods. H. pylori status was examined in gastric materials of all patients. Relationships between HER-2 status in gastric cancers and lymph nodes and H. pylori status were investigated. RESULTS H. pylori was positive in 40 cases (54%), and negative in 34 (46%). While in the primary tissues of H. pylori positive cases, SISH positivity for HER-2 was observed in 13 cases (86%), SISH negativity was observed in 2 (14%), in metastatic lymph nodes 21 cases (72%) were SISH positive and 8 cases (28%) were SISH negative (P=0.005 and P=0.019, respectively). Initial CEA values were high in 18 cases (78%) with positive H. pylori and in 5 cases (22%) with negative H. pylori (P=0.009). While SISH data of patients were negative in 59 cases (80%) and positive in 15 cases (20%) in primary tissues, they were negative in 56 cases (75%) and positive in 18 cases (25%) in lymph nodes. Discrepancy between primary tissue and lymph node results was detected in 3 cases, in which SISH was negative in the primary tissue and HER-2 expression was positive in the lymph nodes. CONCLUSIONS Clinical progression was poor in H. pylori positive cases with HER-2 negativity in primary gastric tissue, but HER-2 positivity in the lymph nodes. SISH positivity can be expected in H. pylori positive cases, and it may be predicted that these cases can benefit from trastuzumab treatment.