When classified BC cases according to the Estrogen Receptor (ER) and Progesterone Receptor (PR) status, significant association of BC risk and rs1820453 was only remained in ER-PR- specified BC subgroup but not in ER+/PR+ subgroup (P =0.004, OR=1.53, 95 % CI=1.14-2.03 and P =0.191, OR=1.18, 95 % CI=0.92-1.50 under allelic model for ER-PR- subgroup and ER+/PR+ subgroup, respectively). Here, ESR1 is linked to breast cancer.