Aim: This study is aimed at determining the human epidermal growth factor receptor-2 (HER-2) gene status in gastric cancers using immunohistochemistry (IHC) and silver DNA in situ hybridization (SISH) technique and investigating the relationship between HER-2 status and clinicopathological variables.
Materials and methods: We examined 104 gastric carcinoma cases with gastrectomy specimens. The age, sex, histopathological tumor type, tumor differentiation, tumor localization, tumor size, invasion depth, lymph node metastasis status, HER-2 IHC evaluation results, and SISH evaluation results of the cases were recorded.
Results: In the present study, the SISH-confirmed HER-2 positivity rate (SISH amplification) is 14.4%. A statistically significant relationship was found between HER-2 status and tumor invasion depth (P = 0.03). It was observed that as the depth of invasion increased, HER-2 positivity decreased. No statistically significant relationship was found between HER-2 status and sex, age, tumor size, differentiation, histopathological classification, lymph node metastasis, and tumor localization (P > 0.05). The rate of HER-2 2+ cases was found to be high.
Conclusion: HER-2 status is negatively correlated with the depth of invasion in gastric cancers, and HER-2 positivity increases as the depth of invasion decreases. HER-2 may be early molecular evidence in oncogenesis. Immunohistochemically, HER-2 2+ cases should be confirmed by the in situ hybridization (ISH) technique.
Keywords: Gastric carcinoma; HER-2 testing; immunohistochemistry; silver DNA in situ hybridization.