数字图像分析（DIA）越来越被用作评估生物标志物的辅助工具，包括侵袭性乳腺癌中的人类表皮生长因子受体2（HER2）。 DIA可以通过呈现HER2染色在APP辅助阅读（AR）中的定量信息来协助病理学家评估HER2。同时，由于新开发的抗体-药物结合物，HER2低表达（没有HER2基因扩增的HER2-1+/2+）已经变得越来越重要。然而，该实体存在较大的观察者之间和内观察者之间的差异性。本研究通过调查DIA和AR在HER2低分类方面在临床使用中的一致性来进行质量控制。在组织微阵列（TMA）核心中评估了来自727名患者761个肿瘤的HER2免疫组化（IHC）得分。当结合HER2-0/1+时，HER2得分的整体一致性为73％（n = 552，加权κ值为0.66）以及88％（n = 669，加权κ值为0.70）。一共有205个得分在一类别上是不一致的，而4个得分则在两个类别上是不一致的。不一致个体中的异质性HER2模式相对较常见，这是HER2低表达乳腺癌的分类中的一个陷阱。相比DIA，AR更常在HER2低亚组（n = 624）中重新指定较低的HER2得分（从HER2-1+到HER2-0）。在异质性和异常染色的情况下，DIA和AR表现出适度的一致性，这代表不一致性和HER2评估中的陷阱。

Digital image analysis (DIA) is used increasingly as an assisting tool to evaluate biomarkers, including human epidermal growth factor receptor 2 (HER2) in invasive breast cancer (BC). DIA can assist pathologists in HER2 evaluation by presenting quantitative information about the HER2 staining in APP assisted reading (AR). Concurrently, the HER2-low category (HER2-1+/2+ without HER2 gene amplification) has gained prominence due to newly developed antibody-drug conjugates. However, major inter- and intraobserver variability have been observed for the entity. The present quality assurance study investigated the concordance between DIA and AR in clinical use, especially concerning the HER2-low category.HER2 immunohistochemistry (IHC) in 761 tumours from 727 patients was evaluated in tissue microarray (TMA) cores by DIA (Visiopharm HER2-CONNECT) and AR. Overall concordance between HER2-scores were 73% (n = 552, weighted-κ: 0.66), and 88% (n = 669, weighted-κ: 0.70), when combining HER2-0/1+. A total of 205 scores were discordant by one category, while four were discordant by two categories. A heterogeneous HER2 pattern was relatively common in the discordant cases and a pitfall in the categorisation of HER2-low BC. AR more commonly reassigned a lower HER2 score (from HER2-1+ to HER2-0) within the HER2-low subgroup (n = 624) compared with DIA.DIA and AR display moderate agreement with heterogeneous and aberrant staining, representing a source of discordance and a pitfall in the evaluation of HER2.© 2023 The Authors. Histopathology published by John Wiley & Sons Ltd.