In 2012, Buckland et al studied 335,062 female participants recruited in 10 European countries from 1992 to 2000, and diagnosed 9009 cases of postmenopausal breast cancer, 1216 cases of premenopausal breast cancer, 5862 cases of ER‐ and PR+, or ER+PR‐, and 1018 cases of ER‐ and PR‐. This evidence concerns the gene ESR1 and breast cancer.