TNFSF11 and breast cancer: In this study, 98 women developed breast cancer and women with high ratio of RANKL/OPG serum levels and high progesterone exhibited a 5.33-fold higher risk of developing breast cancer (OR breast cancer in high RANKL/OPG ratio and high progesterone group = 5.33; 95% CI 1.5–25.4; p = 0.02) [28, 41].