Luo Li, Zhang Xi, Chen Linqiong, Chen Zhuohan, Wang Yuchen, Huang Kaihao, Lin Xiaoyun, Zhu Hongxiang, Du Wangqi
Department of Clinical Laboratory, Taixing People's Hospital Affiliated to Yangzhou University, Taizhou, China.
School of Basic Medical Sciences, Wenzhou Medical University, Cha Mountain Street of High Education Park, Ouhai District, Wenzhou, 325000, China.
BMC Cancer. 2025 Jul 29;25(1):1231. doi: 10.1186/s12885-025-14553-7.
The HER2 immunohistochemistry (IHC) test is an essential method for detecting breast cancer (BC) and plays a pivotal role in guiding personalized treatment strategies. However, inconsistencies persist among different pathologists using IHC, especially for HER2-low and HER2-negative. This may lead to discrepant clinical decisions, potentially impacting patient outcomes. Since HER2 exists in both dimeric and monomeric forms in cells, certain binding sites of diagnostic antibodies on HER2 dimers may be partially obscured in detection. Therefore, accurately detecting HER2 dimers in IHC is crucial for improving diagnostic precision.
We aligned the structures of HER2 heterodimers and Fabs of pertuzumab and trastuzumab binding to HER2, and found they binding in the same region. To overcome the steric hindrance of HER2 dimers, we employed HER2-binding affibody (Aby) and nanobody (Nby) to construct their fusion protein (Nby-Aby) and human heavy chain ferritin (HFn) based nanoparticles (Nby-HFn, Aby-HFn) for detection. Since the Nby and Aby bind HER2 at two distinct regions that are separate from the HER2 dimerization region, effectively minimizing interference from HER2 dimerization in detection. We assessed the detection performance of Nby-Aby in BC tissues and compared it with conventional HER2 diagnostic antibodies using tissue microarrays (TMAs).
The Nby-Aby assay had higher detection sensitivity for HER2-positive cells in BC tissues compared to the conventional method. Additionally, significantly higher HER2 scores were observed in most BC tissues on tissue microarrays (TMAs) compared to those diagnosed using the traditional method. These findings suggest that dual-targeting and overcoming steric hindrance in HER2 IHC detection is a promising strategy to enhance diagnostic precision.
Dual-targeting different regions and overcoming steric hindrance of HER2 in IHC detection through the Nby-Aby fusion protein enhances diagnostic sensitivity, providing a novel strategy for more accurate HER2 IHC assessment in BC diagnosis.
人表皮生长因子受体2（HER2）免疫组织化学（IHC）检测是检测乳腺癌（BC）的重要方法，在指导个性化治疗策略中起着关键作用。然而，不同病理学家使用IHC检测时仍存在不一致性，尤其是对于HER2低表达和HER2阴性的情况。这可能导致临床决策出现差异，潜在地影响患者的治疗结果。由于HER2在细胞中以二聚体和单体形式存在，诊断抗体在HER2二聚体上的某些结合位点在检测中可能会被部分掩盖。因此，在IHC中准确检测HER2二聚体对于提高诊断准确性至关重要。
我们比对了HER2异二聚体以及帕妥珠单抗和曲妥珠单抗与HER2结合的Fab片段的结构，发现它们结合在同一区域。为了克服HER2二聚体的空间位阻，我们采用HER2结合亲合体（Aby）和纳米抗体（Nby）构建它们的融合蛋白（Nby-Aby）以及基于人重链铁蛋白（HFn）的纳米颗粒（Nby-HFn、Aby-HFn）用于检测。由于Nby和Aby在与HER2二聚化区域分开的两个不同区域结合HER2，有效地减少了检测中HER2二聚化的干扰。我们评估了Nby-Aby在BC组织中的检测性能，并使用组织微阵列（TMA）将其与传统HER2诊断抗体进行比较。
与传统方法相比，Nby-Aby检测对BC组织中HER2阳性细胞具有更高的检测灵敏度。此外，与传统方法诊断的结果相比，在组织微阵列（TMA）上大多数BC组织中观察到的HER2评分显著更高。这些发现表明，在HER2 IHC检测中进行双靶点并克服空间位阻是提高诊断准确性的一种有前景的策略。
通过Nby-Aby融合蛋白在IHC检测中双靶点作用于不同区域并克服HER2的空间位阻可提高诊断灵敏度，为BC诊断中更准确的HER2 IHC评估提供了一种新策略。
