TLR4 and synovial sarcoma: The major biological roles of SS have been reported to be associated with inhibiting the production of inflammatory factors via regulating toll-like receptor 4 (TLR4)-nuclear factor kappa beta (NF-κB) and phosphatidylinositol 3-kinase (PI3K)-protein kinase B (PKB)-NF-κB pathway [2, 3].