Prevalence of Foxp3 Positive T Regulatory Cells is Increased during Progression of Cutaneous Squamous Tumors

PURPOSE Forkhead box p3 (Foxp3) positive T regulatory cells (Tregs) have a functionally immunosuppressive property that prevents effector cells from acting against self in autoimmune diseases or a tumor. It is known that Tregs may be highly relevant in cancer progression. Dendritic cells (DCs) induce cutaneous immune response, however several studies have suggested that DCs are involved in immunosuppression. The aim of this study is to evaluate the prevalence of Tregs and DCs infiltration in cutaneous premalignant and malignant squamous lesions. MATERIALS AND METHODS We evaluated Tregs and DCs in skin tissue samples obtained from 83 patients with actinic keratosis, Bowen's disease or squamous cell carcinoma by immunohistochemistry. RESULTS The prevalence of Tregs and DCs was significantly higher in squamous cell carcinoma and Bowen's disease than in actinic keratosis. In addition, the number of DCs was closely correlated with the prevalence of Tregs, and DCs were also located in direct proximity to Tregs. CONCLUSION Tregs is related to cutaneous squamous tumor progression.