Pathology Department, Vall d'Hebron University Hospital, Passeo Vall d'Hebron, 119-129, 08035, Barcelona, Spain.
Autonomous University of Barcelona, Barcelona, Spain.
Diagn Pathol. 2024 Feb 15;19(1):32. doi: 10.1186/s13000-024-01455-8.
Accurate quantification of human epidermal growth factor receptor 2 (HER2) gene amplification is important for predicting treatment response and prognosis in patients with breast cancer. Fluorescence in situ hybridization (FISH) is the gold standard for the diagnosis of HER2 status, particularly in cases with equivocal status on immunohistochemistry (IHC) staining, but has some limitations of non-classical amplifications and such cases are diagnosed basing on additional IHC and FISH. This study investigated the clinical utility of a novel super-resolution fluorescence microscopy technique for the better FISH signal visualization and HER2 FISH classification.
Fourteen breast cancer tissue samples were retrospectively collected between September 2018 and February 2022, and FISH HER2 signal quantification was evaluated by determining the HER2/chromosome 17 centromere (CEP17) ratio and the number of HER2 signals per nucleus in super- versus conventional-resolution images.
Super-resolution images maintained the same overall HER2 diagnosis from routine, but HER2 FISH amplification changed negative to monosomy in two cases. Two Letrozole non-response relapses coincided to monosomy samples. The median number of HER2 signals per nucleus was 7.5 in super-resolution images and 4.0 in conventional-resolution images in HER2-positive samples and 2.8 and 2.1 signals per nucleus, respectively, in HER2-negative samples.
Super-resolution images improved signal visualization, including a significant difference in the number of countable HER2 and CEP17 signals in a single nucleus compared with conventional-resolution images. Increased accuracy of signal quantification by super-resolution microscopy may provide clinicians with more detailed information regarding HER2 FISH status that allows to better FISH classification such as HER2-low samples.
准确量化人类表皮生长因子受体 2（HER2）基因扩增对于预测乳腺癌患者的治疗反应和预后非常重要。荧光原位杂交（FISH）是 HER2 状态诊断的金标准，特别是在免疫组织化学（IHC）染色结果不确定的情况下，但它存在非经典扩增等一些局限性，此类病例基于额外的 IHC 和 FISH 进行诊断。本研究探讨了一种新型超分辨率荧光显微镜技术在更好地可视化 FISH 信号和 HER2 FISH 分类方面的临床应用。
回顾性收集了 2018 年 9 月至 2022 年 2 月期间的 14 例乳腺癌组织样本，通过确定 HER2/染色体 17 着丝粒（CEP17）比值和每个核的 HER2 信号数量，评估超分辨率与常规分辨率图像的 FISH HER2 信号定量。
超分辨率图像保持了与常规图像相同的整体 HER2 诊断，但在两种情况下，HER2 FISH 扩增从阳性变为单体。两例来曲唑无反应复发与单体样本相符。HER2 阳性样本中，超分辨率图像的每个核的 HER2 信号数中位数为 7.5，常规分辨率图像为 4.0；HER2 阴性样本中，超分辨率图像和常规分辨率图像的每个核的 HER2 信号数中位数分别为 2.8 和 2.1。
超分辨率图像改善了信号可视化，包括与常规分辨率图像相比，单个核中可计数的 HER2 和 CEP17 信号数量存在显著差异。超分辨率显微镜对信号定量的准确性提高，可能为临床医生提供更详细的 HER2 FISH 状态信息，从而更好地进行 FISH 分类，如 HER2-低样本。
