(a) Representative results of COBRA of PRTFDC1 Region 1 and Region 2 in 12 of 47 primary oral squamous-cell carcinoma (OSCC) tissues (in other 35 samples not shown) with positive (HSC-2) and negative (HO-1-N-1) control cell lines. Primary OSCC cases, which showed positive restricted DNA fragments (Arrows), are indicated by asterisks (*). See the legend for Figure 3c for interpretation. (b) Methylation status of PRTFDC1 Regions 1 and 2 in four primary cases of OSCC determined by bisulfite sequencing. See the legend for Figure 3d for interpretation.