MYD88 and synovial sarcoma: Type I IFN positive plasmacytoid DCs (pDCs) and monocytes isolated from peripheral blood mononuclear cells of primary SS patients show upregulation of TLR7, as well as, the downstream signaling molecules MyD88 and IRF7, and the DC maturation marker, radical S-adenosyl methionine domain containing 2 (RSAD2) (40).