循环肿瘤细胞(CTCs)主要基于上皮细胞黏附分子(EpCAM)进行富集。虽然研究表明，EpCAM低表达的CTC亚群不能被这种方法所捕获，但目前对其预后和预测性相关性以及与EpCAM阳性CTCs的关系所知甚少。我们开发了一种免疫磁力法，使用针对Trop-2和CD-49f的抗体，独立于EpCAM对转移性乳腺癌患者的CTCs进行富集，并表征其EpCAM表达。分析单个表达高和低的EpCAM CTCs的DNA，探究其染色体畸变和 预测性突变。此外，我们比较了使用该抗体混合物和EpCAM基础富集在CellSearch系统中捕获CTCs。两种抗体协同作用，捕获CTCs。EpCAM高表达的CTCs患者的总体和无进展生存率更差。EpCAM高和低表达的CTCs具有类似的染色体畸变和突变，表明其具有密切的进化关系。从EpCAM降解的部分中顺序富集CTCs，得到了一群CTCs，这些CTCs不依赖于EpCAM，但具有预测性信息。我们的数据表明，EpCAM低表达的CTCs可以作为有价值的肿瘤替代物材料，尽管它们可能比EpCAM高表达的CTCs在预后上不太相关，但如果使用EpCAM依赖技术无法检测到CTCs，则具有特殊的优势。 © 2023作者（们） 。

Circulating tumour cells (CTCs) are mainly enriched based on the epithelial cell adhesion molecule (EpCAM). Although it was shown that an EpCAM low-expressing CTC fraction is not captured by such approaches, knowledge about its prognostic and predictive relevance and its relation to EpCAM-positive CTCs is lacking.We developed an immunomagnetic assay to enrich CTCs from metastatic breast cancer patients EpCAM independently using antibodies against Trop-2 and CD-49f and characterised their EpCAM expression. DNA of single EpCAM high expressing and low expressing CTCs was analyzed regarding chromosomal aberrations and predictive mutations. Additionally, we compared CTC-enrichment on the CellSearch system using this antibody mix and the EpCAM based enrichment.Both antibodies acted synergistically in capturing CTCs. Patients with EpCAM high-expressing CTCs had a worse overall and progression-free survival. EpCAM high- and low-expressing CTCs presented similar chromosomal aberrations and mutations indicating a close evolutionary relationship. A sequential enrichment of CTCs from the EpCAM-depleted fraction yielded a population of CTCs not captured EpCAM dependently but harbouring predictive information.Our data indicate that EpCAM low-expressing CTCs could be used as a valuable tumour surrogate material-although they may be prognostically less relevant than EpCAM high-expressing CTCs-and have particular benefit if no CTCs are detected using EpCAM-dependent technologies.© 2023. The Author(s).