FOXP3 and oral cavity squamous cell carcinoma: For example, exosomal circ-0069313 promotes its function by maintaining the level of Foxp3 transferred to Tregs in oral squamous cell carcinoma, and Foxp3 degradation can be inhibited in Tregs via the sponging of miR-325-3p; both of these mechanisms contribute to immune evasion by tumor cells (101).