ESR1 and cancer: In contrast, for women postmenopausal at diagnosis, we observed a significant inverse association (all cancers, OR: 0.6, 95% CI: 0.4 to 0.9; invasive, OR: 0.6, 95% CI: 0.4 to 0.9; ER+/PR+, OR: 0.6, 95% CI: 0.4 to 0.9; Pheterogeneity all ≤ 0.01).