ESR1 and breast cancer: There was a significant association for hormone receptor-positive ductal breast cancer: ORs per category increase were 1.34 (95% CI: 1.14–1.59) for ER+, 1.33 (95% CI: 1.09–1.61) for PR+ and 1.35 (95% CI: 1.11–1.65) for ER+/PR+ breast cancer.