2650.265 0.153 2.991 1.303 (0.095–1.758) 0.084  Menopausal status 0.219 0.154 2.037 1.245 (0.921–1.683) 0.154  Tumor size 0.283 0.154 3.389 1.328 (0.982–1.795) 0.066  Histological grade 0.218 0.099 4.843 1.244 (1.024–1.510) 0.028  Clinical stage 1.017 selleck kinase inhibitor 0.169 36.097 2.766 (1.985–3.855) 0.000  LN BAY 1895344 research buy metastasis 0.382 0.158 5.858 1.465 (1.075–1.996) 0.016  ER 0.190 0.153 1.525 1.209 (0.895–1.633) 0.217  PR 0.114 0.154 0.548 1.121 (0.829–1.515) 0.459  Her2 0.550 0.155 12.600 1.733 (1.279–2.437) 0.000  NQO1 0.447 0.157 8.055 1.563 (1.148–2.128) 0.005 Multivariate

           Histological grade 0.207 0.109 3.629 1.230 (0.994–1.521) 0.057  Clinical stage 0.906 0.175 26.929 2.475 (1.758–3.485) 0.000  LN metastasis 0.222 0.168 1.756 1.249 (0.889–1.736) 0.185  Her2 0.394 0.161 5.990 1.484 (1.082–2.035) 0.014  NQO1 0.372 0.181 4.216 1.450 (1.017–2.067)

0.040 B: Coefficient; SE: standard error; Wald: Waldstatistic; Erastin mw HR: hazard ratio. To further substantiate the importance of high NQO1 expression in breast cancer progression, we analyzed DFS and 10-year OS of 176 breast cancer cases using the Kaplan–Meier method and found that patients with high NQO1 expression had lower DFS and 10-year OS than those with low NQO1 expression (both P < 0.0001) (Figure  4). In addition, the expression of NQO1 was strongly associated with DFS and 10-year OS rates of patients with both early-stage tumors (P = 0.024) and late-stage tumors (P = 0.015) (Figure  5). Similarly, for patients with either Her2 low or high expression, high NQO1 expression showed significantly worse DFS and Olopatadine 10-year OS than those with low NQO1 expression (P = 0.010 and P = 0.023, respectively)

(Figure  6). Figure 4 Kaplan–Meier survival curves in patients with high and low NQO1 expression. (A) and (B) show comparison of DFS and 10-year OS, respectively, in NQO1 low-expression (L) and high-expression (H) patients. Figure 5 Kaplan–Meier survival curves of in early and late stage patients. (A) and (B) show comparison of DFS and 10-year OS, respectively, in NQO1 (L) and (H) patients of early stage. (C) and (D) show comparison of DFS and 10-year OS, respectively in NQO1 (L) and (H) patients of late stage. Figure 6 Kaplan–Meier survival curves in patients with Her2 positive and negative expression. (A) and (B) show comparison of DFS and 10-year OS, respectively, in NQO1 (L) and (H) patients with Her2 negative expression. (C) and (D) show comparison of DFS and 10-year OS, respectively, in NQO1 (L) and (H) patients with Her2 positive expression. Discussion NQO1 was first identified by Ernster and Navazio in the late 1950s [21]. After decades of research, considerable data has demonstrated that NQO1 can protect against natural and exogenous quinones. NQO1 expression in most human tissue types also suggests that it may function primarily in an antioxidant capacity in these cells.