SSX1 and synovial sarcoma: This has been particularly true since the discovery of highly specific genetic lesions [t(x;18), SYT-SSX1, SSX2, and SSX4 fusion genes] in synovial sarcoma tumors that clinically distinguish this particular this tumor type (Colwell et al., 2002; Amary et al., 2007; Weinbreck et al., 2007).