25. Expression of human epidermal growth factor receptor 2 in gastric cancer with different scoring systems and its relationship with clinicopathological features

Objective: To compare the expression of human epidermal growth factor receptor 2 (HER2) under different scoring systems in gastric cancer and its relationship with clinicopathological features.
Methods: Clinicopathological data were retrospectively reviewed of 270 patients between January to December 2009 in the Department of Surgery at Peking University School of Oncology. Tumor specimens were collected. The expression of HER2 protein was detected by immunohistochemistry.
Results: HER2 (3+) positive rate is different by the new and traditional scoring system, respectively 6.7% and 3.3% (P=0.076), HER2 positive rate (2+/3+) in gastric cancer is 8.5% by the new immunohistochemical scoring system. HER2 protein has a higher over expression rate in big size tumor (diameter ≥5 cm), highly/moderated differentiated tumor and intestinal type tumor. Multivariate analysis showed that the tumor size is the independent factor that influences the over expression of HER2 protein.
Conclusions: HER2 (3+) positive rate is different by the new and traditional scoring system. HER2 over expression has a relationship with its clinicopathological features.