Validation of the diagnostic model of the four DMPs in EAC

After that, we verified the usefulness of this model in EAC diagnosis based on the β value and risk score between 24 EAC samples and 11 normal squamous esophagus samples in GSE89181 dataset. We then constructed the receiver operating characteristics (ROC) using the pROC R package according to a previous study (Robin et al., 2011) and obtained the area under the curve (AUC) value for the specificity and sensitivity. Afterwards, we performed the same analysis for the GSE72872, GSE81334 and GSE104707 data. And usefulness of this model in early staged EAC diagnosis was also verified in stage I EAC cancers of TCGA and GSE89181 by using the same method.