Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai, 200032, China.
Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
BMC Cancer. 2023 Jul 13;23(1):656. doi: 10.1186/s12885-023-11134-4.
Breast cancer (BC) with low human epidermal growth factor receptor 2 (HER2) expression is attracting much attention due to the breakthrough progress of novel anti-HER2 antibody-drug conjugates. HER2 expression is examined in patients with HER2-low BC and their distant metastases in this study, so as to further clarify the dynamic characteristics of HER2 low status in the process of disease progression.
Patients diagnosed with HER2 low breast cancer (defined as IHC1+ or IHC2+/ISH-) between 2012 and 2021 were included in this study. We evaluated HER2 expression of primary sites and metastatic sites, compared the impact of different clinicopathological parameters on HER2 status of metastases and compared the overall survival and disease-free survival of patients with different HER2 status in metastases.
Ninety-eight patients were included. All HER2 IHC scores were confirmed and the consistent rate with the original pathological report was 81.1%. 27.6% of the patients showed different HER2 status in metastases. The HER2 discordance rate differed among different metastatic sites (p = 0.040). The higher the T stage of the primary BC, the higher the rate of HER2 discordance was observed (p = 0.042). For the specimen type of metastasis, HER2 discordant rate was higher in surgical specimen than biopsy (p = 0.050). No difference of HER2 discordance rate was found between HER2-1+ and HER2-2+ patients. But comparing HER2 IHC score, HER2-2+ patients were less likely to have consistent metastatic HER2 levels than HER2-1+ patients (p = 0.006). No difference in survival outcomes was observed between patients with different HER2 status in metastases.
There is a possibility of HER2 expression alteration in the metastases of HER2-low breast cancer. And the rate of altered HER2 low expression was different among different metastatic sites, different T stages of primary BC and specimen type of metastasis. No prognostic significance was observed.
由于新型抗 HER2 抗体药物偶联物的突破性进展，低人表皮生长因子受体 2（HER2）表达的乳腺癌（BC）引起了广泛关注。本研究在 HER2 低 BC 患者及其远处转移灶中检查 HER2 表达，以进一步阐明疾病进展过程中 HER2 低状态的动态特征。
纳入 2012 年至 2021 年间诊断为 HER2 低乳腺癌（定义为 IHC1+或 IHC2+/ISH-）的患者。我们评估了原发部位和转移部位的 HER2 表达，比较了不同临床病理参数对转移部位 HER2 状态的影响，并比较了转移部位不同 HER2 状态患者的总生存和无病生存。
共纳入 98 例患者。所有 HER2 IHC 评分均得到确认，与原始病理报告的一致性率为 81.1%。27.6%的患者在转移灶中表现出不同的 HER2 状态。不同转移部位的 HER2 不一致率不同（p=0.040）。原发 BC 的 T 分期越高，HER2 不一致率越高（p=0.042）。对于转移灶的标本类型，手术标本的 HER2 不一致率高于活检（p=0.050）。HER2-1+和 HER2-2+患者的 HER2 不一致率无差异。但比较 HER2 IHC 评分，HER2-2+患者的转移 HER2 水平一致性较 HER2-1+患者更有可能降低（p=0.006）。转移灶中不同 HER2 状态患者的生存结局无差异。
HER2 低表达乳腺癌的转移灶中存在 HER2 表达改变的可能性。并且改变的 HER2 低表达率在不同的转移部位、原发 BC 的不同 T 分期和转移灶的标本类型之间不同。未观察到预后意义。
