Figure 3

Receiver operating characteristic (ROC) curves of serum HER2 ECD for predicting the status of tissue HER2 positivity with 95% confidence interval (CI; dotted line). (A) The area under the ROC curve (AUC) for the entire cohort of 2,860 patients was 0.697 (95% CI = 0.679–0.714, P < 0.001). In subgroup analyses, AUCs tended to increase with indexes of the tumor extent: (B,C) AUC (95% CI) = 0.659 (0.637–0.682)/0.783 (0.711–0.763) in lymph node (LN)-negative/-positive subgroups; and (D–F) AUC (95% CI) = 0.620 (0.592–0.647)/0.720 (0.695–0.746)/0.778 (0.734–0.818) in stage I/II/III subgroups. The P values of all ROC curves were <0.001.