Assessment of ERBB2 and EGFR gene amplification and protein expression in gastric carcinoma by immunohistochemistry and fluorescence in situ hybridization

BACKGROUND: The goal of this study was to investigate ERBB2(HER2) and EGFR gene amplification and protein expression in gastric cancer. Fluorescence in situ hybridization (FISH) and immunohistochemistry were used to analyze ERBB2 and EGFR gene amplification and protein expression in 69 cases of gastric cancer. RESULTS: FISH analysis revealed that 20.3% of the cases exhibited ERBB2 gene amplification. Increases in ERBB2 copy number and gene amplification were present in 52.2% of the samples. Expression of the ERBB2 protein was observed in 42.0% of cases. FISH analysis detected EGFR gene amplification in 29.0% of samples. Increases in EGFR copy number and gene amplification occurred in 57.9% of samples, and EGFR protein expression was present in 52.2% of samples. Both ERBB2 and EGFR gene amplification were 3 cases (4.3%), but abnormalities in both ERBB2 and EGFR gene copy number were present 36.2% of samples. ERBB2 and EGFR gene amplification were significantly associated with the depth of tumor invasion (P < 0.05) and lymph node metastasis (P < 0.05), but not with sex, age, or histological type (P > 0.05). CONCLUSIONS: Our data indicated that ERBB2 and EGFR genetic abnormalities were associated with the prognosis of gastric cancer. Clinical assessment of ERBB2 and EGFR amplification may represent an important factor for the development of personalized treatment programs for gastic cancer.