ESR1 and breast cancer: We combined the data from stage I and stage II, compared with rs10878441 AA genotype, CC genotype was significantly connected with poor prognosis in breast cancer (HR=1.69, 95% CI: 1.18-2.42, P=0.004), which were still significantly connected with breast cancer OS when adjusted for age at diagnosis, education, occupation, age at menarche, number of live births, breastfeeding duration, abortion, menopause, TNM stage, tumor size, histopathologic classification, grade, lymph node, ER, PR, and HER2 (HR=2.19, 95% CI: 1.30-3.70, P=0.003) (Table 5 and Figure 1).