Epidemiologic Study of Human Epidermal Growth Factor Receptor 2 Expression in Advanced/Metastatic Gastric Cancer: an Assessment of Human Epidermal Growth Factor Receptor 2 Status in Tumor Tissue Samples of Gastric and Gastro-Esophageal Junction Cancer.
OBJECTIVE
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.


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.
Department of Surgery, Kosin University College of Medicine, Busan, Korea .
Kyung Won
KW
Seo
Pusan National University Hospital, Busan, Korea .
Taeyong
T
Jeon
Yeungnam University Medical Center, Daegu, Korea .
Sewon
S
Kim
Chosun University Hospital, Gwangju, Korea .
Sung Soo
SS
Kim
Inje University Busan Paik Hospital, Busan, Korea .
Kwanghee
K
Kim
Inje University Haeundae Paik Hospital, Busan, Korea .
Byoung-Jo
BJ
Suh
Pusan National University Yangsan Hospital, Yangsan, Korea .
Sunhwi
S
Hwang
Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea .
SeongHee
S
Choi
Keimyung University Dongsan Medical Center, Daegu, Korea .
Seungwan
S
Ryu
Dongnam Institute of Radiological and Medical Sciences, Busan, Korea .
Jae Seok
JS
Min
Gyeongsang National University Hospital, Jinju, Korea .
Young-Joon
YJ
Lee
Dankook University Hospital, Cheonan, Korea .
Ye Seob
YS
Jee
Daegu Catholic University Medical Center, Daegu, Korea .
Hyeondong
H
Chae
Chonbuk National University Medical School, Jeonju, Korea .
Doo Hyun
DH
Yang
Department of Surgery, Kosin University College of Medicine, Busan, Korea .
Sang Ho
SH
Lee
Immunohistochemistry; In situ hybridization; Incidence; Receptor, ErbB-2; Stomach neoplasms