SSX1 and osteosarcoma: Osteosarcoma was characterized by the presence of GAGE (40% 2/5), MAGEA1 (60% 3/5), PRAME (40% 2/5), NY-ESO1 (40% 2/5), PASD1 (60% 3/5), SLLP1 (60% 3/5), SSX1 (80% 4/5).