SSX1 and synovial sarcoma: Synovial sarcoma (SS) is a rare soft tissue sarcoma that occurs in adolescents and young adults, with a pathognomonic t (X; 18) (p11.2; q11.2) chromosomal translocation, fusing the SS18 (formerly known as SYT) gene with the SSX1, SSX2, or SSX4 gene (Clark et al., 1994; Shipley et al., 1994).