Figure 2. Detection of serum PNPO concentration and calculation of receiver operating characteristic (ROC) curves. (A) Measurement of PNPO concentration in the peripheral blood of women without tumor (Normal) and patients with fibroadenomas (Benign) or IDC (Malignant). * P < 0.05. (B) Relative PNPO levels in matched serum samples from IDC patients before (Pre-operative) and after (Post-operative) surgery. * P < 0.05. (C) ROC curves for the identification of breast IDC patients vs. non-cancer patients (n = 30, respectively) based on the concentration of PNPO in serum (P < 0.05). (D) ROC curves for the identification of breast IDC patients vs. non-cancer patients (n = 30, respectively) based on the concentration of COL5A1 in serum (P > 0.05). (E) ROC curves for the identification of breast IDC patients vs. non-cancer patients (n = 30, respectively) based on the concentration of PNPO and COL5A1 in serum (P < 0.05). AUC, the area under the curve; IDC, breast invasive ductal carcinoma; n, number of cases.