Resumen de Expresión y amplificación del gen HER2 en el cáncer gástrico avanzado
Ivan Roa, Jeannie Slater Morales, Daniel Carvajal, Kurt Schalper, Gonzalo De Toro, Raúl Ares, Anakaren Game, Jorge León, Xabier de Aretxabala
Background: 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.
