TLR9 and synovial sarcoma: Antimalaria drugs, such as hydroxychloroquine (HCQ) and chloroquine (CQ), are small molecule inhibitors that are known to act as a TLR9, and to a lesser extend as TLR7 and TLR8, antagonist, and are currently used as monotherapy or in conjunction with other therapies for the treatment of SLE, rheumatoid arthritis and SS (140).