Institute of Pathology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Chariteplatz 1, 10117, Berlin, Germany.
Institute of Informatics, Bioinformatics Solution Center, Freie Universität (FU), Takustr. 9, 14195, Berlin, Germany.
J Cancer Res Clin Oncol. 2023 Mar;149(3):1049-1061. doi: 10.1007/s00432-022-03944-z. Epub 2022 Mar 5.
Perioperative chemo-(radio-) therapy is the accepted standard in European patients with locally advanced adenocarcinoma of the esophagogastric junction or stomach (AEG/AS). However, 30-85% of patients do not respond to this treatment. The aim of our study was the identification of predictive biomarkers in pre-therapeutic endoscopic tumor biopsies from patients with histopathologic response (Becker-1) versus non-response (Becker-2/3) to preoperative chemotherapy.
Formalin-fixed paraffin-embedded biopsies from 36 Caucasian patients (Becker-1 n = 11, Becker-2 n = 7, Becker-3 n = 18) with AEG/AS, taken prior to neoadjuvant chemotherapy were selected. For RNA expression analysis, we employed the NanoString nCounter System. To identify genomic alterations like single nucleotide variants (SNV), copy number variation (CNV) and fusion events, we used Illumina TST170 gene panel. For HER2 and FGFR2 protein expression, immunostaining was performed. Furthermore, we analyzed the microsatellite instability (MSI) and Epstein-Barr virus (EBV) infection status by EBER in situ hybridization.
Heat map and principal component analyses showed no clustering by means of gene expression according to regression grade. Concerning two recently proposed predictive markers, our data showed equal distribution for MSI (Becker-1: 2; Becker-2: 1; Becker-3: 3; out of 29 tested) and EBV infection was rare (1/32). We could not reveal discriminating target genes concerning SNV, but found a higher mutational burden in non-responders versus responders and fusion (in 6/14) and CNV events (in 5/14) exclusively in Becker-3.
Although we could not identify discriminating target genes, our data suggest that molecular alterations are in general more prevalent in patients with AEG/AS belonging to the non-responding Becker group 3.
围手术期化疗（放化疗）是治疗欧洲局部进展期胃食管结合部或胃腺癌（AEG/AS）患者的标准治疗方法。然而，30-85%的患者对此治疗方法没有反应。本研究的目的是在术前化疗有组织病理学反应（Becker-1）和无反应（Becker-2/3）的患者的术前内镜肿瘤活检中鉴定预测生物标志物。
选择 36 名白种人 AEG/AS 患者（Becker-1 n=11，Becker-2 n=7，Becker-3 n=18）术前新辅助化疗前的福尔马林固定石蜡包埋活检。采用 NanoString nCounter 系统进行 RNA 表达分析。为了鉴定基因组改变，如单核苷酸变异（SNV）、拷贝数变异（CNV）和融合事件，我们使用了 Illumina TST170 基因面板。对 HER2 和 FGFR2 蛋白表达进行免疫组化染色。此外，我们通过 EBER 原位杂交分析微卫星不稳定性（MSI）和 Epstein-Barr 病毒（EBV）感染状态。
热图和主成分分析显示，根据回归分级，基因表达没有聚类。关于最近提出的两个预测标志物，我们的数据显示 MSI 的分布相等（Becker-1：2；Becker-2：1；Becker-3：3；29 例中 3 例），而 EBV 感染罕见（32 例中 1 例）。我们没有发现关于 SNV 的有区别的靶基因，但在无反应者和有反应者中发现更高的突变负担，并且在 Becker-3 中仅发现融合（14 例中 6 例）和 CNV 事件（14 例中 5 例）。
尽管我们没有发现有区别的靶基因，但我们的数据表明，分子改变在一般属于无反应 Becker 组 3 的 AEG/AS 患者中更为普遍。
