RESUMEN
The malignant transformation in gastric cancer is a multistep, complex process caused by numerous genetic and epigenetic changes, and smoking habits clearly effects on the predisposition to gastric cancer. The aim of this study was to evaluate the status of HER2 protein in gastric cancer patients. The immunohistochemical staining was performed using two tests, based on primary antibodies against HER2, rabbit polyclonal (HerceptTest, Dako) and rabbit monoclonal (4B5, Roche), respectively. According on the used diagnostic test, negative status [0-1 (+)] of HER2 was evaluated form 37% to 89% of cases, respectively. The [(2 (+)] score was obtained in 11% - 43% of cases, and positive score [3(+)] was found in 20% of cases. The concordance between immunohistochemical tests was estimated in 23% cases, but higher IHC scores were indicated for [4B5] antibody. The evaluation of HER2 based on different diagnostic systems may result in different levels of HER2 expression. However, evaluation of HER2 status is certainly an important tool during the diagnosis of gastric cancer patients, indicating the new therapeutic strategies.