SS18 and synovial sarcoma: The first group of tumors can be subcategorized into three further subgroups: (1) sarcomas, accounting for 15–20% of cases, carrying a recurrent translocation such as FUS-CHOP in myxoid liposarcoma (MLPS) and SS18-SSX in synovial sarcoma (SS) (Figure 2A); (2) sarcomas with mutations on specific genes, such as c-KIT or platelet-derived growth factor receptors (PDGFR) mutation in gastrointestinal stromal tumor (GIST) (Figure 2B); (3) sarcomas with distinct amplification, such as the 12q14-15 amplicon in well-differentiated liposarcoma (WDLPS).