Methylation status of TFPI-2 determined by qMSP assay. (A) Box plots of the TFPI-2 methylation level as determined by the qMSP assay. The amount of methylated TFPI-2 was normalized to the amount of ACTB and is expressed as a percentage of that in IVD (given as 100%). N, normal oral tissues; P1-P4, OSCC tissues classified according to pathological stage. In each box plot, the whiskers represent the 10th and 90th percentiles, the lower and upper limits of the box indicate the 25th and 75th percentiles, and the red line is the mean. (B) ROC curve obtained using TFPI-2 methylation to detect OSCC. The AUROC was 0.79. (C) ROC curve obtained using TFPI-2 methylation to detect early-stage OSCC (P1 and P2). The AUROC was 0.82.