Ma Xiuli, Zhou Lixin, Wu Qi, Jia Ling, Diao Xinting, Kang Qiang, Huang Xiaozheng, Liu Yiqiang, Hu Taobo, Long Mengping
Department of Pathology, Peking University Cancer Hospital, Beijing 100083, China.
Department of Breast Surgery, Peking University People's Hospital, Beijing 100044, China.
Life (Basel). 2023 Dec 25;14(1):31. doi: 10.3390/life14010031.
As an important therapeutic target in breast cancer, HER2 expression assessed by immunohistochemistry plays a critical role in breast cancer treatment. Recent advances in HER2 antibody-drug conjugate therapy have enabled patients with HER2-low expression breast cancer to benefit from the drugs. However, it is not known whether the HER2-low expression in breast cancer FFPE blocks would be lost as storage time increased. In this study, we aimed to assess the loss of HER2 antigenicity in stored FFPE blocks of breast cancer and the rescue effect of modifying the protocol of antigen staining. We selected archived HER2-low breast cancer FFPE blocks with stored time ranging from 1 year to over 15 years and re-detected the expression of HER2. Our study showed that HER2 antigenicity loss increased with storage time and could cause false negativity in HER2-low detection. Moreover, we showed that by either increasing the antigen retrieval time or applying the tyramide signal amplification (TSA) kit, the HER2 signal can be rescued and detected in about half of the cases with HER2-low loss without causing false positivity.
作为乳腺癌的一个重要治疗靶点，通过免疫组织化学评估的HER2表达在乳腺癌治疗中起着关键作用。HER2抗体药物偶联物治疗的最新进展使HER2低表达乳腺癌患者能够从这些药物中获益。然而，尚不清楚乳腺癌福尔马林固定石蜡包埋（FFPE）组织块中HER2低表达是否会随着储存时间的增加而丧失。在本研究中，我们旨在评估储存的乳腺癌FFPE组织块中HER2抗原性的丧失情况以及修改抗原染色方案的挽救效果。我们选择了存档的HER2低表达乳腺癌FFPE组织块，其储存时间从1年到超过15年不等，并重新检测HER2的表达。我们的研究表明，HER2抗原性丧失随储存时间增加，可导致HER2低表达检测出现假阴性。此外，我们还表明，通过延长抗原修复时间或应用酪胺信号放大（TSA）试剂盒，在约一半HER2低表达丧失的病例中可以挽救并检测到HER2信号，且不会导致假阳性。
