Evaluation of Her2 Positivity in Gastric Cancer Using Two Different Methods: A Prospective Study

ABSTRACT BACKGROUND: Stomach cancer is one of the most common gastrointestinal tract tumors. Its incidence varies according to ethnic group, geographical conditions, dietary habits, economic status, lifestyle and Helicobacter pylori prevalence. Genetic factors play a major role in the pathogenesis of gastric cancer, and the human epidermal growth factor receptor 2 Her2/neu (c-erb B2) gene is one of these factors. METHOD: The objective of this study is to compare any correlation between the amplification level of Her2/neu gene in gastric cancer by real-time polymerase chain reaction (RT-PCR) with Her2 protein overexpression obtained from the same tissue and studied with immunohistochemisry (IHC), and in the event of positivity, to determine its relationshipwith other known prognostic factors such as age, gender, stage, tumor localization and histological type. RESULTS: IHC results indicated Her2 overexpression in 5 (10%) patients and RT-PCRindicated amplification also in 5 (10%) patients. There was no significant correlation between the results determined by the two methods (p> 0.05). Additionally, no statistically significant difference was detected between prognostic factors and gene expressions in tumor tissues (p> 0.05). CONCLUSION: Her2 gene amplification and protein overexpression can potentially contribute to tumor development. Further studies are needed to evaluate false negativity, investigate patient survival in terms of its contribution to prognosis, and corroborate our hypothesis.