TNFSF11 and breast carcinoma: Finally, evaluation of OPG levels in postmenopause (a state known to protect from breast cancer) suggested that serum OPG levels are significantly (p = 0.01) higher (Fig. 7a) in postmenopause vs premenopause; the opposite tendency (p = 0.0001) was true for serum RANKL (Fig. 7b).