ESR1 and breast cancer: Stratifying the cases by hormone receptor, the association appeared significant only among hormone receptor-positive (ER+, PR+, ER+/PR+) breast cancer: The OR per category increase in urinary cadmium was 1.34 (95% CI: 1.14–1.56) (p-trend < 0.001) for ER+, 1.36 (95% CI: 1.13–1.63) (p-trend = 0.001) for PR+ and 1.37 (95% CI: 1.14–1.65) (p-trend = 0.001) for ER+/PR+ breast cancer (Table 2).