SS18 and synovial sarcoma: As shown in a recent meta-analysis of 10 studies comprising 902 patients with synovial sarcoma, there are no significant differences in overall survival and disease-specific survival rates between patients with synovial sarcoma expressing the SYT-SSX1 and SYT-SSX2 fusion gene; however, SYT-SSX1 seems to represent an unfavorable prognostic factor of progression- and metastasis-free survival [11].