SSX2 and synovial sarcoma: SSX2 and SSX4 expression have been found in all of the cancer types listed above as well as neuroblastoma, gastric cancer, ovarian cancer, synovial sarcoma, mesothelioma (SSX2), pancreatic cancer (SSX4), and intrahepatic cholangiocarcinoma (SSX4) (Table 2) [22, 76–92].