ESR1 and neoplasm: There was a significantly worse PFS for clinical tumor stages III-IV (HR: 4.68, 95% CI: 3.52–6.22) compared to clinical tumor stages 0-II, and worse PFS for tumors that were ER-negative (HR: 1.83, 95% CI: 1.36–2.45), PR-negative (HR: 1.83, 95% CI: 1.38–2.43), HER2-positive (HR: 1.46, 95% CI: 1.04–2.07), or triple-negative (HR: 1.88, 95% CI: 1.35–2.63).