[620] HER2 Protein Over-Expression in Proximal and Distal Gastric Cancers: An Immunohistochemical and Clinicopathological Comparison Study of 957 Cases.

Xiang Shan Fan, Jie Yu Chen, An Ning Feng, Hong Yan Wu, Jason S Gold, Qin Huang. Nanjing Drum Tower Hospital, Jiangsu, China; VA Boston Healthcare System and Harvard Medical School, West Roxbury, MA

Background: Gastric cancer is the second most common cause of cancer death in China. Despite advances in treatment, the outcome for advanced gastric cancer remains poor. HER2 gene amplification and over-expression, which represents a potential therapeutic target, was recently reported in 10-40% of gastric cancers. The relative expression of HER2 in proximal and distal gastric cancers remains unknown. The aim of this study was to compare HER2 expression and its correlation with clinicopathological variables between proximal and distal gastric cancers in Chinese patients.
Design: We retrospectively reviewed a prospectively acquired pathology database for gastric cancer resections with HER2 immunostain results over the period from January 2007 through August 2009. We identified 957 consecutive cases including 513 proximal and 444 distal gastric cancers. HER2 immunoreactivity was scored on a 0-3 scale, according to the ToGA study criteria. Correlations between HER2 expression and clinicopathological variables were sought. Chi-square and Spearman correlation tests were used to assess significance.
Results: HER2 expression in both proximal and distal gastric cancers was significantly higher in the Lauren intestinal type (p<0.001) and grade 2 (p<0.001) gastric cancers as compared to the Lauren diffuse type and grade 3 tumors, respectively. In distal gastric cancers, HER2 expression was significantly higher in stage IV (p<0.001) and in patients with distant metastasis (p<0.001). No statistically significant difference was found in HER2 over-expression between proximal (11% score 3, 25% scores 2 and 3) and distal (8% score 3, 18% scores 2 and 3) gastric cancers (p=0.08).
Conclusions: The rate of HER2 over-expression was similar between proximal and distal gastric cancers. HER2 over-expression significantly correlated with the Lauren intestinal type and grade 2 tumors in the entire series, and with distant metastasis and stage IV in distal gastric cancers only.
Category: Gastrointestinal

Tuesday, March 1, 2011 9:30 AM

Poster Session III # 158, Tuesday Morning

 

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