Nuciforo Paolo, Thyparambil Sheeno, Aura Claudia, Garrido-Castro Ana, Vilaro Marta, Peg Vicente, Jimenez José, Vicario Rocio, Cecchi Fabiola, Hoos William, Burrows Jon, Hembrough Todd, Ferreres Juan Carles, Perez-Garcia José, Arribas Joaquin, Cortes Javier, Scaltriti Maurizio
Molecular Oncology Laboratory, Vall d'Hebron Institute of Oncology, Passeig Vall d'Hebron 119-129, 08035 Barcelona, Spain.
Universitat Autònoma de Barcelona, Plaça Cívica, 08193 Bellaterra (Cerdanyola del Vallès), Spain.
Mol Oncol. 2016 Jan;10(1):138-147. doi: 10.1016/j.molonc.2015.09.002. Epub 2015 Sep 15.
Current methods to determine HER2 (human epidermal growth factor receptor 2) status are affected by reproducibility issues and do not reliably predict benefit from anti-HER2 therapy. Quantitative measurement of HER2 may more accurately identify breast cancer (BC) patients who will respond to anti-HER2 treatments.
Using selected reaction monitoring mass spectrometry (SRM-MS), we quantified HER2 protein levels in formalin-fixed, paraffin-embedded (FFPE) tissue samples that had been classified as HER2 0, 1+, 2+ or 3+ by immunohistochemistry (IHC). Receiver operator curve (ROC) analysis was conducted to obtain optimal HER2 protein expression thresholds predictive of HER2 status (by standard IHC or in situ hybridization [ISH]) and of survival benefit after anti-HER2 therapy.
Absolute HER2 amol/μg levels were significantly correlated with both HER2 IHC and amplification status by ISH (p < 0.0001). A HER2 threshold of 740 amol/μg showed an agreement rate of 94% with IHC and ISH standard HER2 testing (p < 0.0001). Discordant cases (SRM-MS-negative/ISH-positive) showed a characteristic amplification pattern known as double minutes. HER2 levels >2200 amol/μg were significantly associated with longer disease-free survival (DFS) and overall survival (OS) in an adjuvant setting and with longer OS in a metastatic setting.
Quantitative HER2 measurement by SRM-MS is superior to IHC and ISH in predicting outcome after treatment with anti-HER2 therapy.
目前用于确定HER2（人表皮生长因子受体2）状态的方法受到可重复性问题的影响，并且不能可靠地预测抗HER2治疗的获益情况。对HER2进行定量测量可能能更准确地识别出对抗HER2治疗有反应的乳腺癌（BC）患者。
我们使用选择反应监测质谱法（SRM-MS），对经免疫组织化学（IHC）分类为HER2 0、1+、2+或3+的福尔马林固定石蜡包埋（FFPE）组织样本中的HER2蛋白水平进行定量。进行了受试者操作特征曲线（ROC）分析，以获得预测HER2状态（通过标准IHC或原位杂交[ISH]）以及抗HER2治疗后生存获益的最佳HER2蛋白表达阈值。
HER2的绝对amol/μg水平与HER2 IHC以及ISH检测的扩增状态均显著相关（p < 0.0001）。HER2阈值为740 amol/μg时，与IHC和ISH标准HER2检测的一致率为94%（p < 0.0001）。不一致的病例（SRM-MS阴性/ISH阳性）呈现出一种称为双微体的特征性扩增模式。在辅助治疗中，HER2水平>2200 amol/μg与更长的无病生存期（DFS）和总生存期（OS）显著相关，在转移性疾病中与更长的OS相关。
通过SRM-MS对HER2进行定量测量在预测抗HER2治疗后的结果方面优于IHC和ISH。
