小染色体维持蛋白2（MCM-2）是比Ki-67更敏感的增殖标志物。本研究旨在评估MCM-2与Oncotype DX复发评分（ODX-RS）之间的关系，并根据TAILORx风险分类确定高风险患者的MCM-2截断值。收入研究的血清受体（HR）阳性HER-2阴性早期乳腺癌患者（pT1-2，pN0-N1，M0），他们具有ODX-RS。根据TAILORx试验，根据ODX-RS将患者分为高风险（ODX-RS≥26）和低风险（ODX-RS<26）两组。再评估病人的甲醛固定石蜡嵌入组织，为MCM-2免疫组织化学染色准备3 µm切片。在两组中评估ODX-RS与MCM-2染色百分比之间的关系。进行ROC曲线分析以确定TAILORx高风险组（ODX-RS≥26）的MCM-2切断值。高风险组的平均MCM-2值显著高于低风险组[(60.2±11.2 vs 34.4±13.8, p<0.001)]。在多元分析中，发现MCM-2（OR：1.27，95% CI：1.08-1.49，p=0.003）和孕激素受体（PR）水平≤10%（OR：60.9，95% CI：4.1-89.7，p=0.003）是指示高风险组的独立因素。MCM-2 水平的增加使处于高风险组的可能性增加了1.27倍。在ROC曲线分析中，最佳MCM-2切断值为50（AUC：0.921，敏感性：86.7%，特异性：96.0%，p<0.001）。本研究是文献中首次调查HR阳性HER-2阴性早期乳腺癌患者ODX-RS和MCM-2水平之间关系的研究。在本研究中，MCM-2是根据TAILORx风险分类鉴定高风险患者的独立危险因素。MCM-2切断值（50）可以帮助无法进行Oncotype DX测试的患者进行辅助化疗决策。© 2023 Ünal等。

The minichromosome maintenance protein-2 (MCM-2) is a more sensitive proliferation marker than Ki-67. This study aimed to evaluate the relationship between MCM-2 and Oncotype DX recurrence score (ODX-RS) and determine an MCM-2 cutoff value in high-risk patients according to TAILORx risk categorization.Hormone receptor (HR) positive HER-2 negative early-stage breast cancer patients (pT1-2, pN0-N1, M0) who had ODX-RS were included in the study. According to the TAILORx trial, patients were divided into two groups with high (ODX-RS ≥26) and low risk (ODX-RS <26) in terms of ODX-RS. Formalin-fixed-paraffin-embedded tissues of patients were re-evaluated, and 3 µm sections were prepared for MCM-2 immuno-histochemical staining. The relationship between ODX-RS and the percentage of MCM-2 staining was evaluated in two groups. The ROC curve analysis was performed to determine the MCM-2 cut-off value for the TAILORx high-risk group (ODX-RS ≥26).The mean MCM-2 value was significantly higher in the high-risk group [(60.2 ± 11.2 vs 34.4 ± 13.8, p < 0.001)]. In the multivariate analysis, MCM-2 (OR: 1.27, 95% CI: 1.08-1.49, p = 0.003) and progesterone receptor (PR) levels ≤10% (OR: 60.9, 95% CI: 4.1-89.7, p = 0.003) were found to be independent factors indicating a high-risk group. A one-unit increase in MCM-2 level increased the likelihood of being in the high-risk group by 1.27 times. In the ROC curve analysis, the optimal MCM-2 cut-off level was 50 (AUC: 0.921, sensitivity: 86.7%, specificity: 96.0%, p < 0.001).Our study is the first study in the literature to investigate the relationship between ODX-RS and MCM-2 levels in HR-positive HER-2 negative early breast-cancer patients. In this study, MCM-2 was an independent risk factor in identifying high-risk patients according to TAILORx risk classification. MCM 2 cut-off value (50) may help the decision on adjuvant chemotherapy in patients where the Oncotype DX test cannot be performed.© 2023 Ünal et al.