ABSTRACT
<p><b>OBJECTIVE</b>To explore the status of HER2 gene amplification and its product HER2 protein expression in gastric carcinoma, so as to aid in patient selection for anti-HER2 targeted chemotherapy.</p><p><b>METHODS</b>Eighty-five cases of gastric carcinoma biopsy tissues were collected. The status of HER2 gene amplification was detected by dual in situ hybridization (dual-ISH). And HER2 protein was detected by immunohistochemistry.</p><p><b>RESULTS</b>HER2 gene amplification was detected in 10/85 (11.8%) cases of gastric carcinoma, and no amplification was detected in 75/85 (88.2%) cases. In the 10 cases with HER2 amplification, HER2 immunoreaction scorings of 3+, 2+ and 0/1+ were present in 7, 2 and 1 cases, respectively. In the 75 cases without HER2 amplification, HER2 immunoreaction scorings of 3+, 2+ and 0/1+ were present in 0, 18 (24.0%) and 57 (76.0%) cases, respectively. Histologically, most gastric carcinoma with amplification of HER2 gene was moderately differentiated tubular adenocarcinoma.</p><p><b>CONCLUSIONS</b>HER2 gene dual-ISH technique is a reliable and objective method for detecting HER2 gene amplification in gastric carcinoma biopsy. Clinically, only few gastric carcinomas show HER2 gene amplification and are suitable candidates for anti-HER2 targeted chemotherapy.</p>