• Journal of Gastric Cancer
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• v.17 no.1
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• pp.52-62
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• 2017

Purpose: The Trastuzumab for gastric cancer (GC) trial identified human epidermal growth factor receptor 2 (HER2) as a predictor of successful treatment with trastuzumab (HER2 receptor targeting agent) among patients with advanced/metastatic GC. To date, the prevalence of HER2 overexpression in the Korean population is unknown. The present study aimed to assess the incidence of HER2 positivity among GC and gastroesophageal (GE) junction cancer samples and the relationship between HER2 overexpression and clinicopathological characteristics in Korean patients. Materials and Methods: Tumor samples collected from 1,695 patients with histologically proven GC or GE junction enrolled at 14 different hospitals in Korea were examined. After gathering clinicopathological data of all patients, HER2 status was assessed by immunohistochemistry (IHC) at each hospital, and IHC 2+ cases were subjected to silver-enhanced in situ hybridization at 3 central laboratories. Results: A total of 182 specimens tested positive for HER2, whereas 1,505 tested negative. Therefore, the overall HER2-positive rate in this study was 10.8% (95% confidence interval=9.3%-12.3%). The HER2-positive rate was higher among intestinal-type cases (17.6%) than among other types, and was higher among patients older than 70 years and 50 years of age, compared to other age groups. Conclusions: Our evaluation of the HER2 positivity rate (10.8%) among Korean patients with GC and GE junction indicated the necessity of epidemiological data when conducting studies related to HER2 expression in GC and GE junction.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7597-7602
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• 2014

Background: Amplification and overexpression of human epidermal growth factor receptor 2 (HER2/neu) oncogene has considerable prognostic value in breast and gastric cancers. This study aimed to evaluate the frequency, overexpression pattern, clinical significance, and concordance between the results for protein expression and gene amplification of HER-2/neu in gastric and gastro-esophageal junction carcinomas. Materials and Methods: In this study, 101 gastric tissue samples which were included in tissue microarray were immunohistochemically examined for overexpression of HER2/neu. Chromogenic in situ hybridization (CISH) was used for HER-2/neu amplification. The correlation of HER2/neu amplification with clinicopathological parameters was also assessed. In addition, concordance between CISH and IHC was detected. Results: This study demonstrated a significant difference in the overexpression of HER2/neu in gastric tumors. The overexpression of HER2/neu was significantly higher in intestinal type, poorly differentiated grade, large size ($5cm{\leq}$) and positive nodal involvement tumors (p-value=0.041, 0.015, 0.038 and 0.071, respectively). Also, amplification of HER2/neu according to CISH test, had a significant positive correlation with tumor size and tumor type (p-value=0.018 and 0.058, respectively).Concordance between CISH and IHC was 76.9% in 101 evaluable samples. Conclusions: IHC/CISH differences were attributed to basolateral membranous immunoreactivity of glandular cells resulting in incomplete membranous reactivity and/or a higher rate of tumor heterogeneity in gastric cancers compared to breast cancers. Therefore, this can be a potential marker for targeted therapy of malignant gastric tumors.

• Journal of Gastric Cancer
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• v.8 no.4
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• pp.210-216
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• 2008

Purpose: Siewert's classification of adenocarcinoma of the esophagogastric junction (AEG) has been widely adopted, but there is a wide discrepancy of the clinicopathological features of AEG of the Asian patients as compared to that of the Western patients. The aim of this study was to investigate the clinicopathological characteristics of AEG according to the Siewert classification. Materials and Methods: Among the patients who underwent surgery for gastric carcinoma in our institution between May 2004 and February 2008, the AEG patients were selected based on their operation records and the photographs according to Siewert's classification. Results: There were 70 AEG patients (3.9%) among the total of 1,778 patients. There were 3 patients (4.3%) with type I, 30 patients (42.8%) with type II and 37 patients (52.8%) with type III. Curative resection (R0) was achieved in 68 cases (97.1%). No significant differences in gender, stage, Barrett's esophagus and the proximal margin were found between the patients with type II and type III AEG. The patients with type III were younger than the patients with type II (59 vs 64 years, respectively, P=0.049). Well differentiated histology (P=0.045) and the intestinal type (P=0.055) were significantly more frequent in the patients with type II as compared with that in the patients with type III. Conclusion: There was a striking difference of the Asian patients from the Western patients for the incidence of AEG (and especially type I). Some of the differences between type II and type III patients were similar to those of the previous Western studies. A large study is needed to investigate whether these features are typical in the Korean population.