SSX1 and gastrointestinal stromal tumor: Molecular characterization already has clinical implications for some subtypes of sarcoma, either for prognosis (e.g., poor prognosis for patients with KIT exon 11 deletion in GIST, FKHR-PAX3 expression in metastatic rhabdomyosarcoma and SYT-SSX1 fusion type in synovial sarcoma) [47]–[49], treatment (adjuvant radiotherapy), or response to treatment (e.g. better response to imatinib for GIST with exon 11 mutation than with exon 9 mutation) [50].