ESR1 and invasive ductal breast carcinoma: Most patients were postmenopausal (55.8%) and had invasive ductal carcinomas not otherwise specified (NOS, 81.8%), tumor size >2 cm (69.6%), positive lymph nodes ≥4 (52.0%), ER/PgR-positive (77.7%) and HER2-negative (76.9%) status.