Open AccessSignificant intratumoral heterogeneity of human epidermal growth factor receptor 2 status in gastric cancer: A comparative study of immunohistochemistry, FISH , and dual‐color in situ hybridization
Author(s) -
Kanayama Kazuki,
Imai Hiroshi,
Yoneda Misao,
Hirokawa Yoshifumi S.,
Shiraishi Taizo
Publication year - 2016
Publication title -
cancer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 1347-9032
DOI - 10.1111/cas.12886
Subject(s) - biopsy , immunohistochemistry , human epidermal growth factor receptor 2 , cancer , pathology , concordance , in situ hybridization , medicine , fluorescence in situ hybridization , epidermal growth factor receptor , adenocarcinoma , biology , breast cancer , gene expression , biochemistry , chromosome , gene
The assessment of human epidermal growth factor receptor 2 ( HER 2) status is crucial for selecting patients with gastric cancer who may benefit from HER 2‐targeted therapy. Accurate assessment using biopsy specimens is important for patients with advanced‐stage cancer. Intratumoral heterogeneity of HER 2, however, is a major challenge in HER 2 testing. Here, we aimed to examine whether assessment of HER 2 status could be accurately carried out with currently used methods, namely, immunohistochemistry ( IHC ), FISH , and dual‐color in situ hybridization ( DISH ). Human epidermal growth factor receptor 2 status was evaluated in 108 biopsy tissues from patients with gastric adenocarcinoma and 70 matched surgical specimens by IHC , FISH , and DISH ; HER 2 amplification was detected in 11 (10.2%) out of 108 biopsy specimens. The IHC and FISH results were well correlated, and FISH and DISH results were consistent for all cases. The overall concordance rate of HER 2 status between biopsy tissues and surgical specimens was 91.4%. All six discordant cases were false negative on biopsy; of these cases, five showed HER 2 heterogeneity on surgical resection. Assessment of the HER 2 status of biopsy tissues could predict the status of the whole tumor; however, a proportion of these cases may be discordant because of intratumoral heterogeneity.