PGR and breast cancer: With regard to the prognosis associated with HR-specific subtype, the double-positive subgroup constantly exhibited the utmost favorable prognosis, while a significant divergence existed in both OS and BCSS between ER + /PgR + and ER−/PgR + subtype breast cancer (3-year and 5-year OS, 89.2% vs. 80.8% and 81.9% vs. 74.2%, P < 0.0001; 3-year and 5-year BCSS, 93.4% vs. 86.3% and 89.0% vs. 79.5%, P < 0.0001) (Figure S2a, b).