Formalin fixation on HER-2 and PD-L1 expression in gastric cancer:A pilot analysis using the same surgical specimens with different fixation times

作     者：Keita Kai Yukie Yoda Atsushi Kawaguchi Akimichi Minesaki Hironori Iwasaki Shinichi Aishima Hirokazu Noshiro 

作者机构：Department of Pathology Saga University Hospital Department of Surgery Saga University Faculty of Medicine Center for Comprehensive Community Medicine Saga University Faculty of Medicine Department of Pathology and Microbiology Saga University Faculty of Medicine Department of Otolaryngology - Head and Neck Surgery Saga University Faculty of Medicine 

出 版 物：《World Journal of Clinical Cases》 (世界临床病例杂志)

年 卷 期：2019年第7卷第4期

页      面：419-430页

核心收录：

学科分类：10[医学] 

基　　金：Japan Society for the Promotion of Science  JSPS  (16K08650) 

主　　题：Gastric cancer Programmed death-ligand1 Human epidermal growth factor receptor2 Neutral buffered formalin Fixation time 

摘      要：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. Although the importance of standardization of sample fixation has been widely recognized, most of the evidence regarding the fixation duration or type of fixing solution are based on breast *** To investigate the real effects of fixation conditions on HER-2 testing or PD-L1 testing for gastric cancer using gastrectomy *** Thirty-two patients who underwent gastrectomy for gastric cancer were *** resected 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(n = 22) or 10% neutral buffered formalin(NBF)(n = 10).Immunohistochemistry(IHC) of HER-2 and PD-1 was performed, and a pathology examination was conducted. In the HER-2-immunoreactive cases, all four specimens were subjected to dual-color in situ hybridization(DISH). Five cases were assessed as HER-2-positive by IHC and DISH. We used the cut-off values of 1%, 10%, and 50% to assess the IHC findings of *** No significant difference was observed in comparisons between the shorter fixation period groups(6 h, 24 h, and 48 h) and the prolonged fixation period(1 wk) group in the HER-2 and PD-L1 analyses. Although no significant difference was observed between 10% formalin and 10% NBF within 1 wk of fixation, the superiority of 10% NBF was confirmed in a long-term( 3 mo) fixation in both the HER-2 and PD-L1 *** In this small-numbered 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.