Hammond Jonathan, Lambert Nicholas, Voutsadakis Ioannis A
Northern Ontario School of Medicine, Sudbury, ON P3E 2C6, Canada.
Algoma District Cancer Program, Sault Area Hospital, Sault Ste. Marie, ON P6B 0A8, Canada.
Cancers (Basel). 2025 Jul 5;17(13):2252. doi: 10.3390/cancers17132252.
Breast cancer is the most prevalent women's cancer, representing about a third of all cancers diagnosed in women. Estrogen receptor (ER) is an important transcription factor expressed in 70% to 75% of all breast cancers. Of these breast cancers, the majority express ER robustly in 91-100% of tumor cells. However, a minority of breast cancers express ER in intermediate levels between 11% and 90% of tumor cells. The characteristics and outcomes of this intermediate subset of ER-positive breast cancers are not well studied.
We retrospectively reviewed the medical records of all breast cancer patients treated in our Cancer Center over a period of 8 years. Patients were grouped according to the level of ER expression in tumors with negative/low ER expression, intermediate ER expression, and high ER expression, and the groups were compared for tumor characteristics and outcomes.
Patients with high ER levels (91% to 100%) represented 75.6% (600 of 794 patients), patients with intermediate ER expression represented 11.5% of the entire group (91 of 794 patients), and patients with negative/low ER expression (ER expression 0-10%) represented 12.9% of the entire cohort (103 of 794 patients). Patients with intermediate ER expression presented at a younger age than patients with high-ER cancers, as well as a more advanced stage and higher grade. These characteristics were more akin to patients with negative/low ER levels. Mastectomy was the surgical method of resection more commonly in ER-intermediate tumors than in ER-high tumors. The relapse-free survival (RFS) of patients with ER-intermediate cancers was worse than the RFS of patients that expressed ER robustly.
The level of expression of ER defines groups of patients with varying characteristics and prognoses. Patients in the intermediate ER expression group had notable differences from patients in the high ER expression group including younger age, (more often) a higher grade, and low PR positivity. Differences observed between the group of patients with intermediate ER expression and that with high ER expression may help to prioritize therapeutic algorithms.
乳腺癌是女性中最常见的癌症，约占女性确诊癌症总数的三分之一。雌激素受体（ER）是一种重要的转录因子，在所有乳腺癌中70%至75%有表达。在这些乳腺癌中，大多数在91%至100%的肿瘤细胞中强烈表达ER。然而，少数乳腺癌在11%至90%的肿瘤细胞中呈中等水平表达ER。这种ER阳性乳腺癌中间亚组的特征和预后尚未得到充分研究。
我们回顾性分析了本癌症中心8年间所有乳腺癌患者的病历。根据肿瘤中ER表达水平将患者分为ER阴性/低表达、ER中等表达和ER高表达组，并比较各组的肿瘤特征和预后。
ER高表达（91%至100%）的患者占75.6%（794例患者中的600例），ER中等表达的患者占整个队列的11.5%（794例患者中的91例），ER阴性/低表达（ER表达0 - 10%）的患者占整个队列的12.9%（794例患者中的103例）。ER中等表达的患者比ER高表达癌症患者发病年龄更小，分期更晚，分级更高。这些特征更类似于ER阴性/低水平的患者。与ER高表达肿瘤相比，ER中等表达肿瘤更常采用乳房切除术作为手术切除方法。ER中等表达癌症患者的无复发生存期（RFS）比ER强表达患者的RFS更差。
ER表达水平定义了具有不同特征和预后的患者群体。ER中等表达组的患者与ER高表达组的患者有显著差异，包括年龄较小、（更常见）分级较高和孕激素受体（PR）阳性率较低。ER中等表达组和ER高表达组患者之间观察到的差异可能有助于优化治疗方案。
