Meta-analysis has confirmed the disease-related treatment benefits of aromatase inhibitors over tamoxifen when given for 5 years and followed for 10 years, including a 15% decrease in death from ER-positive breast cancer (HR = 0.85; (0.75–0.96), 2p = 0.009) and a 38% decrease in the risk of contralateral breast cancer (HR = 0.62; 0.48–0.80 2p = 0.0003) [43]. Here, CYP19A1 is linked to breast cancer.