ESR1 and neoplasm: Breast surgery type (P = 0.046), clinical tumor size stage (P = 0.023), axillary node status (P < 0.001), STI (P = 0.001), histological grading (P < 0.001), ER (P = 0.003), PR (P < 0.001), HER2 (P < 0.001), and molecular subtype (P < 0.001) were significantly associated with ΔKi67.