Characteristics and prognosis of Her2-negative breast cancer expressing unbalanced hormone receptor.

Hormone receptors(HRs), including the Estrogen receptor(ER) and Progesterone receptor(PR), are essential indicators for Breast cancer therapy, while the unbalanced expression effect remains unclear. 106,742 women diagnosed with HER2-negative BC in SEER from 2010 to 2015 were divided into four groups: ER-negative PR-negative (NN), ER-negative PR-positive (NP), ER-positive PR-negative (PN), ER-positive PR-positive (PP). The survival rate of NP was equal to NN (P = 0.65, Hazard Ratio(HR) = 0.960, 95%Confidence Index(CI):0.807-1.144), but worse than PP(P = 0.00017, HR = 0.695, 95%CI:0.575-0.874). The curve of PN was lower than PP(P < 0.0001, HR = 0.753, 95%CI:0.706-0.803), but significantly higher than NN(P < 0.0001, HR = 0.808, 95%CI:0.754-0.866). The effect of PN was worse than that of PP (P_Surgery < 0.0001, HR = 0.834, 95%CI:0.774 to 0.899; P_Radiation < 0.0001, HR = 0.808, 95%CI:0.726-0.884; P_Chemotherapy < 0.0001, HR = 0.812, 95%CI:0.748-0.881; P_Systemic.therapy < 0.0001, HR = 0.799, 95%CI:0.735-0.869). The C-index of NP and PN prediction models were 0.697 (95%CI: 0.654-1.128) and 0.750 (95%CI: 0.733-0.760), respectively, showing moderate effects. HER2-negative BC with unbalanced HRs expression differs from those with consistent expression. NP and PN have lower long-term survival rates than PP even after systemic treatment. Endocrine resistance may be the cause of poor survival of NP and PN, and should be combined with other treatments such as actual intensive chemotherapy. Although the clinical number of NP breast cancer is small, it still needs attention.