Abstract：
Addition of HER2-targeted treatment in breast cancer is mainly determined by the HER2-receptor status of primary breast cancer tissue, since longitudinal sampling is burdensome and often not feasible. However, tumor heterogeneity and receptor conversion occur and may lead to improper diagnose as disease progresses. It is however possible that patients with their applied receptor status misjudged may benefit from HER2-targeted therapy. Liquid biopsies provide a useful source of information for receptor status and determine prognosis or evaluate therapy effectiveness. In this review, we give a comprehensive overview of current analytical and clinical validity and clinical utility of liquid biopsies for HER2 assessment. We systematically searched publications in Cochrane, Embase, PubMed and Google Scholar databases until April 2021 reporting on HER2-positivity in liquid biopsies and its concordance with tumor tissue, or on prognostic and/or predictive value of HER2-positivity in liquid biopsies. Applying our selection criteria, we identified 57 studies; 43 studies on circulating tumor cells, 13 studies on circulating tumor DNA and 1 study on extracellular vesicles. Most studies showed an association with outcome or treatment response, but used methods differed greatly, lacked a gold standard and evaluated patient groups differently hampering interpretation of results. We conclude that well-designed studies to determine assay validity and clinical validity and utility of HER2 assessment through liquid biopsies are currently lacking.
摘要：
乳腺癌的HER2靶向治疗主要取决于原发性乳腺癌组织的HER2受体状态，因为纵向抽样是繁重的，往往不可行。然而,肿瘤异质性和受体转换的发生，并可能导致不当的诊断，随着疾病的进展。然而，错误判断其应用受体状态的患者可能会从HER2靶向治疗中受益。液体活检为受体状态提供了有用的信息来源，并确定预后或评估治疗有效性。在这次审查中,我们全面概述了用于HER2评估的液体活检的当前分析和临床有效性以及临床实用性.我们系统地搜索了Cochrane的出版物，Embase,截至2021年4月，PubMed和GoogleScholar数据库报告了液体活检中HER2阳性及其与肿瘤组织的一致性，或液体活检中HER2阳性的预后和/或预测价值。应用我们的选择标准，我们确定了57项研究；43项关于循环肿瘤细胞的研究，关于循环肿瘤DNA的13项研究和关于细胞外囊泡的1项研究。大多数研究表明与结果或治疗反应有关，但是使用的方法差异很大，缺乏黄金标准，对妨碍结果解释的患者组进行了不同的评估。我们得出的结论是，目前缺乏精心设计的研究来确定通过液体活检进行HER2评估的测定有效性和临床有效性以及实用性。
