Roa, IvánSlatter, JeannieCarvajal, DanielSchalper, KurtDe Toro, GonzaloAres, RaúlGame, AnakarenLeón, JorgeDe Aretxabala, Xabier2017-03-032017-03-032013Revista Médica de Chile 2013, 141:1411-1419http://hdl.handle.net/11447/996http://dx.doi.org/10.4067/S0034-98872013001100007Background: Overexpression/amplification of the HER2 gene in advanced gastric cancer is a predictor of response to adjuvant therapy with monoclonal antibodies. Aim: To determine the frequency of HER2 gene overexpression and amplification in advanced gastric cancer. Material and Methods: One hundred nine advanced gastric cancer biopsy specimens, from 76 men and 33 women aged 67 ± 14 and 62 ± 12 years respectively, were selected. Three histological patterns (diffuse, intestinal and mixed) were recognized. Automated immunohistochemistry was performed with monoclonal c-erbB-2 (NCL-356) Novocastra. Fluorescent in situ hybridization (FISH) for HER2 was performed in positive cases. Results: In 39% of cases, immunohistochemical staining was negative. It was 1+, 2+ and 3+ positive in 15, 36 and 11% of cases, respectively. It was positive in 16% and 3% of intestinal type and mixed carcinomas, respectively. It was negative in all diffuse carcinomas. FISH was performed in 39 (2 +) cases and in 11 (3 +) cases. The gene amplification was positive in two (2 +) and 11 (3 +) cases (11.9%). The overall concordance between immunohistochemical staining and in situ hybridization was 85%. Conclusions: In advanced gastric cancer, HER2 gene overexpression or amplification was observed in 11% and 12% of cases, respectively.9spaGene amplificationHER2, protein, humanin situ hibridization, fluorescenceImmunohistochemistryArtículo