Salivary PDPN levels showed a similar pattern, being highest in OC (2.65 ± 0.75 ng/mL), followed by leukoplakia (1.40 ± 0.45 ng/mL), and controls (0.72 ± 0.30 ng/mL) (p < 0.001). This evidence concerns the gene PDPN and leukoplakia.