Centre for Oncological Research (CORE), University of Antwerp, Antwerp, Belgium.
Department of Oncology, Antwerp University Hospital, Antwerp, Belgium.
PLoS One. 2019 Sep 4;14(9):e0220906. doi: 10.1371/journal.pone.0220906. eCollection 2019.
Personalized targeted treatment in metastatic breast cancer relies on accurate assessment of molecular aberrations, e.g. overexpression of Human Epidermal growth factor Receptor 2 (HER-2). Molecular interrogation of circulating tumor cells (CTCs) can provide an attractive alternative for real-time biomarker assessment. However, implementation of CellSearch-based HER-2 analysis has been limited. Immunofluorescent (IF) image interpretation is crucial, as different HER-2 categories have been described. Major questions in CTC research are how these IF categories reflect gene expression and amplification, and if we should consider 'medium' HER-2 expressing CTCs for patient selection.
Tumor cells from spiked cell lines (n = 8) and CTCs (n = 116 samples) of 85 metastatic breast cancer patients were enriched using CellSearch. Comparative analysis of HER-2 expression by IF imaging (ACCEPT, DEPArray, and visual scoring) with qRT-PCR and HER-2/neu FISH was performed.
Automated IF HER-2-profiling by DEPArray and ACCEPT delivered comparable results. There was a 98% agreement between 17 trained observers (visual scoring) and ACCEPT considering HER-2neg and HER-2high expressing CTCs. However, 89% of HER-2med expressing CTCs by ACCEPT were scored negative by observers. HER-2high expressing tumor cells demonstrated HER-2/neu gene amplification, whereas HER-2neg and HER-2med expressing tumor cells and CTCs by ACCEPT were copy-number neutral. All patients with HER-2-positive archival tumors had ≥1 HER-2high expressing CTCs, while 80% of HER-2-negative patients did not. High relative gene expression of HER-2 measured on enriched CTC lysates correlated with having ≥1 HER-2high expressing CTCs.
Automated images analysis has enormous potential for clinical implementation. HER-2 characterization and clinical trial design should be focused on HER-2high expressing CTCs.
转移性乳腺癌的个体化靶向治疗依赖于对分子异常的准确评估，例如人表皮生长因子受体 2（HER-2）的过度表达。循环肿瘤细胞（CTC）的分子检测为实时生物标志物评估提供了一种有吸引力的替代方法。然而，基于 CellSearch 的 HER-2 分析的实施受到限制。免疫荧光（IF）图像解释至关重要，因为已经描述了不同的 HER-2 类别。CTC 研究中的主要问题是这些 IF 类别如何反映基因表达和扩增，以及我们是否应该考虑将“中等”HER-2 表达的 CTC 用于患者选择。
使用 CellSearch 从掺入细胞系（n=8）和 85 名转移性乳腺癌患者的 CTCs（n=116 个样本）中富集肿瘤细胞。使用 qRT-PCR 和 HER-2/neu FISH 对 IF 成像（ACCEPT、DEPArray 和视觉评分）的 HER-2 表达进行比较分析。
DEPArray 和 ACCEPT 的自动 IF HER-2 分析提供了可比的结果。在考虑 HER-2neg 和 HER-2high 表达的 CTCs 时，17 名经过培训的观察者（视觉评分）与 ACCEPT 之间的一致性为 98%。然而，通过 ACCEPT 评估的 89%的 HER-2med 表达 CTCs 被观察者评为阴性。HER-2high 表达的肿瘤细胞表现出 HER-2/neu 基因扩增，而 HER-2neg 和 HER-2med 表达的肿瘤细胞和通过 ACCEPT 的 CTCs 则为拷贝数中性。所有具有 HER-2 阳性存档肿瘤的患者均有≥1 个 HER-2high 表达的 CTCs，而 80%的 HER-2 阴性患者则没有。在富集的 CTC 裂解物上测量的 HER-2 的相对高基因表达与有≥1 个 HER-2high 表达的 CTCs 相关。
自动图像分析具有巨大的临床应用潜力。HER-2 特征描述和临床试验设计应集中在 HER-2high 表达的 CTCs 上。
