Fig. 2

Construction of the seven-CpG-based classifier. a Circos plot of epigenome-wide DNA methylation CpG sites. Results are presented as P values ordered by genomic position, including paired t test of the discovery set (green and red symbols) and univariable Cox regression analysis of the training set (orange and blue symbols). b Volcano plot comparing CpG methylation for OSCC tumor and non-tumor tissues. A total of 1490 CpG sites had an absolute value of differential methylation of > 0.4 and a paired t test P value of < 1 × 10⁻⁷ (blue dots). c Heatmap showing methylation of 15 CpG sites in tumor tissues and adjacent non-tumor tissues. d Coefficients of CpG sites calculated by univariate Cox regression and sure independence screening (SIS). After SIS selection, seven probes remained non-zero coefficients