Aim: To study the HER-2/neu protein expression and gene amplification in gastric carcinoma and their relation.
Methods: One hundred and forty-five formalin-fixed and paraffin- embedded tumor tissue samples from Chinese gastric carcinoma patients were studied with immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) methods. Clinicopathologic data about all patients were collected.
Results: The levels of HER-2 3+, HER-2 2+ and HER2 1+ were measurable in 6.9%, 8.3% and 17.2% of the samples, respectively. No HER-2 was stained in 67.6% of the samples. FISH showed that HER-2 gene was amplified in 18 samples, 10 HER-2 3+ samples, 5 HER-2 2+ samples, and 3 HER-2 1+ samples with IHC staining. HER-2 status was not correlated with the sex and age of patients, and tumor size, location or differentiation, but with the depth of invasion, TNM stage, lymph node and distant metastasis as well as histopathological classification of gastric cancer (P < 0.05).
Conclusion: All samples with IHC as HER-2 expression should be analyzed with FISH. Detection of HER-2 gene amplification can assess the malignant biological behaviors and prognosis of gastric cancer.
Keywords: Clinocopathologic significance; Fluorescence in situ hybridization; Gastric carcinoma; HER-2; Immunohistochemistry.