Among these four Wnt ligands, mRNA levels of Wnt3a, Wnt5b and Wnt7b are upregulated in leukoplakia and early stage OSCC, suggesting that if a causality is determined between periodontitis and OSCC, these ligands may participate in initiating malignant transformation of normal oral cells (Figures 1B, 2B). This evidence concerns the gene WNT3A and periodontitis.