Studies have demonstrated that suppression of AhR using siRNA in human periodontal ligament cells and gingival fibroblasts leads to decreased expression of proinflammatory cytokines and apoptosis-related genes, which suggests that AhR activation contributes to persistent inflammation and cellular survival in epulis tissues.181 These molecular findings have significant clinical implications, as they help explain why some epulis lesions persist despite removal of local irritants and may contribute to the varying recurrence rates observed clinically among different epulis subtypes. This evidence concerns the gene AHR and epulis.