ESR1 and neoplasm: Nevertheless, we also observed a tendency with poor prognosis in BCSS for patients with ER/PR or HER-2 negative tumor (HR = 1.552, 95% CI = 0.816–2.954, p = 0.181, HR = 2.048, 95% CI = 0.951–4.408, p = 0.067, and HR = 2.662, 95% CI = 0.916–7.732, p = 0.072, respectively).