For instance, IL-1β and TNF-α can promote the overexpression and abnormal accumulation of mucin in the SGs of SS, thereby leading to SGs dysfunction [29]. Interestingly, apart from exerting a synergistic effect with IL-1β, TNF-α is also considered in some studies to be capable of affecting salivary secretion independently, which is mainly related to the downregulation of the expression of tight junction protein 1 in the SGs [30]. This evidence concerns the gene TNF and synovial sarcoma.