PRDX6 and cancer: PPIA and Prdx6 were antioxidant enzymes, and CD147 was the receptor of PPIA, all of them had been researched in our previous studies [9]–[11], and this study showed that the expression scores of PPIA, Prdx6 and CD147 increased progressively from normal oral mucosa to OSCC, which indicated that the antioxidant enzymes was regulated following the cancer development.