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©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
Formalin fixation on HER-2 and PD-L1 expression in gastric cancer: A pilot analysis using the same surgical specimens with different fixation times
Keita Kai, Yukie Yoda, Atsushi Kawaguchi, Akimichi Minesaki, Hironori Iwasaki, Shinichi Aishima, Hirokazu Noshiro
Keita Kai, Shinichi Aishima, Department of Pathology, Saga University Hospital, Saga 849-8501, Japan
Yukie Yoda, Hironori Iwasaki, Hirokazu Noshiro, Department of Surgery, Saga University Faculty of Medicine, Saga 849-8501, Japan
Atsushi Kawaguchi, Center for Comprehensive Community Medicine, Saga University Faculty of Medicine, Saga 849-8501, Japan
Akimichi Minesaki, Shinichi Aishima, Department of Pathology and Microbiology, Saga University Faculty of Medicine, Saga 849-8501, Japan
Akimichi Minesaki, Department of Otolaryngology - Head and Neck Surgery, Saga University Faculty of Medicine, Saga 849-8501, Japan
Author contributions: Kai K conceived and designed the study. Kai K, Yoda Y, Kawaguchi A, Minesaki A, Iwasaki H, Aishima S and Noshiro H researched and analyzed data, and wrote, edited and reviewed the manuscript. The manuscript is an original work of all authors. All authors gave final approval for publication. Kai K takes full responsibility for the work as a whole, including the study design, access to data and the decision to submit and publish the manuscript.
Institutional review board statement: This study protocol was reviewed and approved by the Ethics Committee of the Faculty of Medicine at Saga University (approval no. 29-74)
Conflict-of-interest statement: The authors declare that they have no conflicts of interest.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Keita Kai, MD, PhD, Associate Professor, Department of Pathology, Saga University Hospital, 5-1-1 Nabeshima, Saga City, Saga 849-8501, Japan. kaikeit@cc.saga-u.ac.jp
Telephone: +81-952-343264 Fax: +81-952-342055
Received: November 25, 2018
Peer-review started: November 26, 2018
First decision: December 15, 2018
Revised: December 24, 2018
Accepted: December 29, 2018
Article in press: December 30, 2018
Published online: February 26, 2019
ARTICLE HIGHLIGHTS
Research background
The needs for human epidermal growth factor receptor 2 (HER-2) and/or programmed death-ligand 1 (PD-L1) evaluations in gastric cancer are dramatically increasing. However, most of the evidences regarding the fixation duration or type of fixing solution are based on breast cancer.
Research motivation
As the HER-2 expression of gastric cancer is unique, we speculate that the effects of the fixative conditions on the determination of HER-2 results in gastric cancer may differ from those of breast cancer.
Research objectives
To investigate the real effects of fixation conditions on HER-2 testing or PD-L1 testing for gastric cancer using gastrectomy specimens.
Research methods
Resected gastric specimens were each divided into four pieces and fixed in four strictly controlled different durations (6 h, 24 h, and 48 h, and 1 wk) by 10% formalin or 10% neutral buffered formalin (NBF). Immunohistochemistry (IHC) of HER-2 and PD-1 was performed, and a pathology examination was conducted.
Research results
Prolonged fixation did not show inferiority within the 1-wk period for the assessment of both HER-2 and PD-L1 expressions. The superiority of 10% NBF was confirmed in the long-term (> 3 mo) fixation.
Research conclusions
In this pilot study, prolonged fixation within 1 wk showed no inferiority in HER-2 or PD-L1 testing. However, a large-numbered prospective study is needed to obtain conclusive results.
Research perspectives
Our findings provide supporting information for the interpretation of HER-2 and/or PD-L1 testing for cases beyond the ASCO/CAP fixation recommendation due to unavoidable circumstances.
