ESR1 and breast cancer: We found that high MAGI1 expression is associated with a lower risk of relapse in ER+/HER2− BC treated with tamoxifen at the univariate (HR 0.58 [0.43–0.80], q = 0.001), and multivariate level (HR 0.50 [0.34–0.73], q = 0.001).