ESR1 and neoplasm: higher tumour gradeno correlation with axillary lymph node status or tumour size or HER2 amplificationpoorer prognosisindication for need for additional chemotherapeutic treatmentpositive correlation with ER status (p < 0.005)positive correlation with PR status (p < 0.005)inverse correlation to Nottingham prognostic indexinverse correlation to membrane EGFRsignificantly shorter overall survival and relapse - free survivaltamoxifen resistance