Naoyuki Tominaga, Takuji Gotoda, Megumi Hara, Matthew D. Hale, Takayoshi Tsuchiya, Jun Matsubayashi, Shin Kono, Chika Kusano, Takao Itoi, Kazuma Fujimoto, Fuminori Moriyasu, Heike I. Grabsch
Abstract
National guidelines recommend trastuzumab for treatment of patients with metastatic HER2-positive gastric cancer (GC). There is currently no guideline indicating the number of biopsy specimens and the location from which they should be obtained to reliably determine the human epidermal growth factor receptor 2 (HER2) status in GC. The aim of this pilot study was (a) to quantify HER2-positive tumor cells in different tumor regions to assess the spatial heterogeneity of HER2 expression and (b) to establish the required number of biopsy specimens and the location from which they should be obtained within the tumor to achieve concordance between HER2 expression status in the biopsy specimens and the resection specimen.
HER2 expression was quantified in six different regions of 24 HER2-positive GC and in six virtual biopsy specimens from different luminal regions. Intratumoral regional heterogeneity and concordance between HER2 status in the biopsy specimens and the resection specimen were analyzed.
HER2-positive cells were more frequent in the luminal tumor surface compared with deeper layers (p < 0.001). GCs with differentiated histological features were more commonly HER2 positive (p < 0.001). Assessment of HER2 expression status in five biopsy specimens was sufficient to achieve 100 % concordance between the biopsy specimens and the resection specimen.
This is the first study to suggest preferential HER2 positivity at the luminal surface in GC and to establish a minimum number of biopsy specimens needed to obtain a biopsy HER2 result which is identical to that from the whole tumor. Our study suggests that HER2 testing in five tumor-containing endoscopic biopsy specimens from the proximal (oral) part of the tumor is advisable. The results from this pilot study require validation in a prospective study.
Pharmacology, Toxicology and Pharmaceutical Science
1
4%
Economics, Econometrics and Finance
1
4%
Other
1
4%
Unknown
10
40%
Attention Score in Context
Attention Score in Context
This research output has an Altmetric Attention Score of 1. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 20 May 2015.
All research outputs
#18,410,971
of 22,805,349 outputs
Outputs from Gastric Cancer
#399
of 597 outputs
Outputs of similar age
#192,595
of 266,311 outputs
Outputs of similar age from Gastric Cancer
#6
of 7 outputs
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