ESR1 and breast cancer: For ER + breast cancer patients, the results of univariate and multivariate COX analysis demonstrated that lymph node metastasis (HR = 4.079, P = 0.001), vascular invasion (HR = 3.603, P = 0.040) and PR status (HR = 0.346, P = 0.015) were independent predictive factors for DFS (Table 4).