SSX1 and synovial sarcoma: In synovial sarcoma, gene expression analysis revealed high levels of EGFR, SSX [80], ERBB2, IGFBP2, and IGF2 expression [81]: this subtype of sarcoma is characterized by a translocation (X,18; p11,q11) which determines a fusion gene between SS18 and SSX1 (or SSX2) that exerts a key role in this neoplasm [82].