ESR1 and breast carcinoma: Younger age (below 35 years), breast-conserving surgery, tumour size larger than 2 cm, the presence of endovascular or lymphatic tumour emboli, a close resection margin (< 3 mm), ER-negativity, TN breast cancer, negative staining for bcl-2 expression, and high levels of Ki67 expression correlated with shorter RFS.