ESR1 and invasive ductal breast carcinoma: Of these patients, 88.0% (n = 4,161), 86.2% (n = 4,077), 85.3% (n = 4,036), 82.2% (n = 3,885), and 77.2% (n = 3,651) were ER-positive, invasive ductal carcinoma, HER2-negative, grade II–III, and PR-positive, respectively.