Melanoma cells have also acquired mechanisms to subvert the immune-stimulatory functions of pDCs, such as secrete immunosuppressive cytokines, including IL-10, TGF-β and PGE2, to suppress the expression level of TLR7/9 and IRF7, resulting in pDCs producing only a small amount of I-IFN (43, 73). Here, TLR7 is linked to melanoma.