In terms of the levels of MDSCs, PMN-MDSCs, M-MDSCs and Tregs in the peripheral blood of breast cancer patients, no statistically significant correlations were found with age, menopause status, histological grading, vascular invasion, molecular subtypes, ER level, PR level, Her-2 level, Ki-67 level and AR level (all P > 0.05). Here, ESR1 is linked to breast cancer.