A hypomethylation of signal transducers and activators of transcription 5 (STAT5) promoter and prostaglandin-endoperoxide synthase 2 (PTGS2) promoter, increased methylation at two CpG sites of TNF-α and TLR2 gene in gingival tissues from chronic periodontitis patients has been reported [48]. The gene discussed is PTGS2; the disease is chronic periodontitis.