ROC curve analyses revealed that methylation status of each individual genes significantly distinguished primary carcinoma from normal mucosa, as measured by sensitivity, specificity, and AUC value (MPPED2: sensitivity 0.804, specificity 0.978, AUC 0.890; IKZF1: sensitivity 0.761, specificity 0.978, AUC 0.875; RSPO3: sensitivity 0.783, specificity 0.978, AUC 0.858; COL23A1: sensitivity 0.783, specificity 0.978, AUC 0.840; EPHA6: sensitivity 0.587, specificity 0.935, AUC 0.736) (Fig. 5f, Additional file 4: Table S3). Here, COL23A1 is linked to carcinoma.