ESR1 and breast cancer: Interestingly, the findings in TAILORx and RxPONDER trials, which used Oncotype DX 21-gene recurrence score (RS) to stratify patients with ER-positive, HER2-negative, lymph node-negative (TAILORx) or node-positive with 1–3 positive nodes (RxPONDER) breast cancer, suggested that the performance and the used threshold of Oncotype DX depended on the menopausal status.