The short-term survival of ER- patients was generally worse than patients with ER+ disease; the five-year overall survival (OS) and breast cancer-specific survival (BCSS) rates were 78.3% and 80.6% for ER+ cohort while corresponding survival rates for ER− BC were 60.6% and 64.5% (Figure 1a,b). This evidence concerns the gene ESR1 and breast cancer.