ESR1 and breast cancer: However, Zhang et al. [22] demonstrated a possible variation of the optimal cut-off to improve cause-specific and overall survival by breast cancer subtype (RDI ≥ 85% for subtype ER+/progesterone+/HER2-, and RDI ≥ 75% for subtype ER-/progesterone-/HER2- [triple negative]) in a retrospective study with 674 patients from the United States receiving NACT or ACT.