Figure 5. ROC curve of the serum YKL-40 levels of 120 breast cancer patients and 30 controls.

The estimated area under the ROC curve was observed as AUC = 0.877 with 95%CI. = 0.823 to 0.931 (P-value<.001) The best cut-off of serum YKL-40 level was observed as “60” based on the maximization of Yuden index. The predictive diagnosis of breast cancer according the cut-off of serum level = 60 was 65.8% in sensitivity, 96.7% in specificity, 98.8% in PPV, and 41.4% in NPV.