Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
Breast Cancer Res. 2022 Mar 21;24(1):22. doi: 10.1186/s13058-022-01519-x.
There is an increasing interest in HER2-low breast cancer with promising data from clinical trials using novel anti-HER2 antibody-drug conjugates. We explored the differences in clinicopathological characteristics and survival outcomes between HER2-low and HER2-IHC 0 breast cancer.
Using nationwide data from the Korean Breast Cancer Registry between 2006 and 2011, 30,491 patients with stages I to III breast cancer were included in the analysis: 9,506 (31.2%) in the HER2-low group and 20,985 (68.8%) in the HER2-IHC 0 group. Kaplan-Meier and Cox proportional hazards regression survival analysis were used to compare breast cancer-specific survival between the two groups.
HER2-low breast cancer was more frequent in patients with hormone receptor-positive breast cancer than in those with triple-negative breast cancer. In patients with hormone receptor-positive breast cancer, HER2-low breast cancer was associated with fewer T4 tumors, higher histological grade, and a negative lymphatic invasion. In patients with triple-negative breast cancer, HER2-low breast cancer was associated with a high lymph node ratio and positive lymphatic invasion. HER2-low breast cancer was significantly associated with a lower Ki-67 labeling index. No significant difference was observed in overall survival between the two groups. HER2-low breast cancer showed significantly better breast cancer-specific survival than HER2-IHC 0 breast cancer, regardless of the hormone receptor status. In multivariate analysis, the impact of low HER2 expression on breast cancer-specific survival was significant only in triple-negative breast cancer (HRs, 0.68; 95% CI, 0.49-0.93; P = 0.019).
These findings suggest that the biology and clinical impact of low HER2 expression can differ according to the hormone receptor status and support the need for further investigation on the understanding of the biology of HER2-low breast cancer.
随着新型抗 HER2 抗体药物偶联物临床试验数据的不断涌现，人们对 HER2 低表达乳腺癌的兴趣日益浓厚。本研究旨在探讨 HER2 免疫组织化学（IHC）0 与 HER2 低表达乳腺癌的临床病理特征和生存结局差异。
利用韩国乳腺癌注册中心 2006 年至 2011 年期间的全国性数据，纳入 30491 例 I 至 III 期乳腺癌患者，其中 9506 例（31.2%）为 HER2 低表达组，20985 例（68.8%）为 HER2 IHC 0 组。采用 Kaplan-Meier 法和 Cox 比例风险回归生存分析比较两组间乳腺癌特异性生存差异。
与三阴性乳腺癌相比，HER2 低表达乳腺癌在激素受体阳性乳腺癌患者中更为常见。在激素受体阳性乳腺癌患者中，HER2 低表达乳腺癌与 T4 肿瘤较少、组织学分级较高和无淋巴血管侵犯相关。在三阴性乳腺癌患者中，HER2 低表达乳腺癌与较高的淋巴结比率和阳性淋巴血管侵犯相关。HER2 低表达乳腺癌与较低的 Ki-67 标记指数显著相关。两组总生存无显著差异。无论激素受体状态如何，HER2 低表达乳腺癌的乳腺癌特异性生存均显著优于 HER2 IHC 0 乳腺癌。多因素分析显示，低 HER2 表达对乳腺癌特异性生存的影响仅在三阴性乳腺癌中具有统计学意义（HR，0.68；95%CI，0.49-0.93；P=0.019）。
这些发现表明，低 HER2 表达的生物学和临床影响可能因激素受体状态而异，支持进一步研究以加深对 HER2 低表达乳腺癌生物学的理解。
