ESR1 and breast cancer: For the estrogens, among women premenopausal at diagnosis, a doubling of follicular estradiol was suggestively positively associated with invasive and ER+/PR+ breast cancer (invasive, OR: 1.2, 95% CI: 1.0 to 1.4; ER+/PR+, OR: 1.2 95% 0.9 to 1.5).