ESR1 and breast cancer: However, among postmenopausal women in the AMBER Consortium Study, it was inversely associated with the risk of all subtypes of breast cancer (≥30 vs. 20–24.9 kg/m2, ER+ OR = 0.62, 95% CI = 0.38–1.01; ER– OR = 0.78, 95% CI = 0.44–1.41; TNBC OR = 0.68, TNBC 95% CI = 0.29–1.56).