ESR1 and neoplasm: Adjustment for age, tumor size, nodal status, histological grade, ER and PR status, and chemotherapy given left Z-4OH tam and Z-endoxifen as the only factors in the final models with HR = 4.27 (95% CI = 1.35–13.58) and HR = 3.70 (95% CI = 1.03–13.25), respectively.