NQO1 and breast cancer: 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).