Zhang Huina, Ramineni Madhurya, Li Xiaoxian
Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, 14624, USA.
Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, Rochester, NY, 14624, USA.
Hum Pathol. 2025 Aug;162:105820. doi: 10.1016/j.humpath.2025.105820. Epub 2025 May 27.
The assessment of estrogen receptor (ER) expression in breast cancer, has traditionally been performed using ligand-binding assays, followed by immunohistochemistry, and is widely used to predict tumor response to endocrine therapy. ER-low positive breast cancer, formally defined in the 2020 ASCO/CAP testing guidelines, represents a small subset of invasive breast cancers characterized by 1 %-10 % of ER staining. Emerging evidence suggests that ER-low positive tumors constitute a heterogeneous group in terms of clinicopathologic features, molecular profiles, prognosis, and responsiveness to endocrine therapy. These tumors frequently behave more like ER-negative cancers, often displaying a more aggressive clinical course compared to classic ER-positive tumors. The clinical benefit of endocrine therapy in this subset remains uncertain, posing a significant challenge in determining the optimal treatment strategies. This review offers both a historical perspective and a comprehensive, up-to-date analysis of recent advancements in the understanding of ER-low positive breast cancer, with a focus on tumor biology, pathological evaluation, and clinical implications.
传统上，乳腺癌中雌激素受体（ER）表达的评估是通过配体结合试验进行的，随后进行免疫组织化学检测，并且广泛用于预测肿瘤对内分泌治疗的反应。ER低阳性乳腺癌在2020年美国临床肿瘤学会/美国病理学家学会（ASCO/CAP）检测指南中被正式定义，它是浸润性乳腺癌的一个小亚组，其特征是ER染色为1%-10%。新出现的证据表明，ER低阳性肿瘤在临床病理特征、分子特征、预后和对内分泌治疗的反应方面构成一个异质性群体。这些肿瘤的行为通常更类似于ER阴性癌症，与经典的ER阳性肿瘤相比，其临床病程往往更具侵袭性。内分泌治疗在这一亚组中的临床获益仍不确定，这在确定最佳治疗策略方面构成了重大挑战。本综述既提供了历史视角，也对ER低阳性乳腺癌认识方面的最新进展进行了全面、最新的分析，重点关注肿瘤生物学、病理评估和临床意义。
